High severity8.8NVD Advisory· Published Apr 20, 2017· Updated May 13, 2026

CVE-2016-3734

Description

Cross-site request forgery (CSRF) vulnerability in markposts.php in Moodle 3.0 through 3.0.3, 2.9 through 2.9.5, 2.8 through 2.8.11, 2.7 through 2.7.13 and earlier allows remote attackers to hijack the authentication of users for requests that marks forum posts as read.

Affected packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
moodle/moodlePackagist	< 2.7.14	2.7.14
moodle/moodlePackagist	>= 2.8, < 2.8.12	2.8.12
moodle/moodlePackagist	>= 2.9, < 2.9.6	2.9.6
moodle/moodlePackagist	>= 3.0, < 3.0.4	3.0.4

Patches

01408d619ba8

MDL-53755 forum: Check session when marking posts

https://github.com/moodle/moodleAndrew NicolsApr 8, 2016via ghsa

commit

3 files changed · +5 −4

mod/forum/index.php+2 −2 modified

@@ -230,7 +230,7 @@
                 } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                     $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                   $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                   $forum->id.'&amp;mark=read&amp;sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                 } else {
                     $unreadlink = '<span class="read">0</span>';
                 }
@@ -368,7 +368,7 @@
                     } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                         $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                       $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                       $forum->id.'&amp;mark=read&sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                     } else {
                         $unreadlink = '<span class="read">0</span>';
                     }

mod/forum/lib.php+2 −2 modified

@@ -3714,7 +3714,7 @@ function forum_print_discussion_header(&$post, $forum, $group = -1, $datestring
                     echo $post->unread;
                     echo '</a>';
                     echo '<a title="'.$strmarkalldread.'" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php">' .
+                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">' .
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.$strmarkalldread.'" /></a>';
                     echo '</span>';
                 } else {
@@ -5402,7 +5402,7 @@ function forum_print_latest_discussions($course, $forum, $maxdiscussions = -1, $
                 if ($forumtracked) {
                     echo '<a title="'.get_string('markallread', 'forum').
                          '" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;mark=read&amp;returnpage=view.php">'.
+                         $forum->id.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">'.
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.get_string('markallread', 'forum').'" /></a>';
                 }
                 echo '</th>';

mod/forum/markposts.php+1 −0 modified

@@ -55,6 +55,7 @@
 $user = $USER;
 
 require_login($course, false, $cm);
+require_sesskey();
 
 if ($returnpage == 'index.php') {
     $returnto = new moodle_url("/mod/forum/$returnpage", array('id' => $course->id));

d98c24659935

MDL-53755 forum: Check session when marking posts

https://github.com/moodle/moodleAndrew NicolsApr 8, 2016via ghsa

commit

3 files changed · +5 −4

mod/forum/index.php+2 −2 modified

@@ -230,7 +230,7 @@
                 } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                     $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                   $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                   $forum->id.'&amp;mark=read&amp;sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                 } else {
                     $unreadlink = '<span class="read">0</span>';
                 }
@@ -368,7 +368,7 @@
                     } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                         $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                       $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                       $forum->id.'&amp;mark=read&sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                     } else {
                         $unreadlink = '<span class="read">0</span>';
                     }

mod/forum/lib.php+2 −2 modified

@@ -3843,7 +3843,7 @@ function forum_print_discussion_header(&$post, $forum, $group=-1, $datestring=""
                     echo $post->unread;
                     echo '</a>';
                     echo '<a title="'.$strmarkalldread.'" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php">' .
+                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">' .
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.$strmarkalldread.'" /></a>';
                     echo '</span>';
                 } else {
@@ -5530,7 +5530,7 @@ function forum_print_latest_discussions($course, $forum, $maxdiscussions = -1, $
                 if ($forumtracked) {
                     echo '<a title="'.get_string('markallread', 'forum').
                          '" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;mark=read&amp;returnpage=view.php">'.
+                         $forum->id.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">'.
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.get_string('markallread', 'forum').'" /></a>';
                 }
                 echo '</th>';

mod/forum/markposts.php+1 −0 modified

@@ -55,6 +55,7 @@
 $user = $USER;
 
 require_login($course, false, $cm);
+require_sesskey();
 
 if ($returnpage == 'index.php') {
     $returnto = new moodle_url("/mod/forum/$returnpage", array('id' => $course->id));

e90e0ea5700e

MDL-53755 forum: Check session when marking posts

https://github.com/moodle/moodleAndrew NicolsApr 8, 2016via ghsa

commit

3 files changed · +5 −4

mod/forum/index.php+2 −2 modified

@@ -245,7 +245,7 @@
                 } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                     $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                   $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                   $forum->id.'&amp;mark=read&amp;sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                 } else {
                     $unreadlink = '<span class="read">0</span>';
                 }
@@ -383,7 +383,7 @@
                     } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                         $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                       $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                       $forum->id.'&amp;mark=read&sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                     } else {
                         $unreadlink = '<span class="read">0</span>';
                     }

mod/forum/lib.php+2 −2 modified

@@ -3741,7 +3741,7 @@ function forum_print_discussion_header(&$post, $forum, $group = -1, $datestring
                     echo $post->unread;
                     echo '</a>';
                     echo '<a title="'.$strmarkalldread.'" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php">' .
+                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">' .
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.$strmarkalldread.'" /></a>';
                     echo '</span>';
                 } else {
@@ -5433,7 +5433,7 @@ function forum_print_latest_discussions($course, $forum, $maxdiscussions = -1, $
                 if ($forumtracked) {
                     echo '<a title="'.get_string('markallread', 'forum').
                          '" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;mark=read&amp;returnpage=view.php">'.
+                         $forum->id.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">'.
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.get_string('markallread', 'forum').'" /></a>';
                 }
                 echo '</th>';

mod/forum/markposts.php+1 −0 modified

@@ -55,6 +55,7 @@
 $user = $USER;
 
 require_login($course, false, $cm);
+require_sesskey();
 
 if ($returnpage == 'index.php') {
     $returnto = new moodle_url("/mod/forum/$returnpage", array('id' => $course->id));

7873e36f0cc0

MDL-53755 forum: Check session when marking posts

https://github.com/moodle/moodleAndrew NicolsApr 8, 2016via ghsa

commit

3 files changed · +5 −4

mod/forum/index.php+2 −2 modified

@@ -230,7 +230,7 @@
                 } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                     $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                   $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                   $forum->id.'&amp;mark=read&amp;sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                 } else {
                     $unreadlink = '<span class="read">0</span>';
                 }
@@ -368,7 +368,7 @@
                     } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                         $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                       $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                       $forum->id.'&amp;mark=read&sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                     } else {
                         $unreadlink = '<span class="read">0</span>';
                     }

mod/forum/lib.php+2 −2 modified

@@ -3805,7 +3805,7 @@ function forum_print_discussion_header(&$post, $forum, $group=-1, $datestring=""
                     echo $post->unread;
                     echo '</a>';
                     echo '<a title="'.$strmarkalldread.'" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php">' .
+                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">' .
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.$strmarkalldread.'" /></a>';
                     echo '</span>';
                 } else {
@@ -5486,7 +5486,7 @@ function forum_print_latest_discussions($course, $forum, $maxdiscussions = -1, $
                 if ($forumtracked) {
                     echo '<a title="'.get_string('markallread', 'forum').
                          '" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;mark=read&amp;returnpage=view.php">'.
+                         $forum->id.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">'.
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.get_string('markallread', 'forum').'" /></a>';
                 }
                 echo '</th>';

mod/forum/markposts.php+1 −0 modified

@@ -55,6 +55,7 @@
 $user = $USER;
 
 require_login($course, false, $cm);
+require_sesskey();
 
 if ($returnpage == 'index.php') {
     $returnto = forum_go_back_to(new moodle_url("/mod/forum/$returnpage", array('id' => $course->id)));

1f5c494f761e

MDL-53755 forum: Check session when marking posts

https://github.com/moodle/moodleAndrew NicolsApr 8, 2016via ghsa

commit

3 files changed · +5 −4

mod/forum/index.php+2 −2 modified

@@ -228,7 +228,7 @@
                 } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                     $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                   $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                   $forum->id.'&amp;mark=read&amp;sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                 } else {
                     $unreadlink = '<span class="read">0</span>';
                 }
@@ -366,7 +366,7 @@
                     } else if ($unread = forum_tp_count_forum_unread_posts($cm, $course)) {
                         $unreadlink = '<span class="unread"><a href="view.php?f='.$forum->id.'">'.$unread.'</a>';
                         $unreadlink .= '<a title="'.$strmarkallread.'" href="markposts.php?f='.
-                                       $forum->id.'&amp;mark=read"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
+                                       $forum->id.'&amp;mark=read&sesskey=' . sesskey() . '"><img src="'.$OUTPUT->pix_url('t/markasread') . '" alt="'.$strmarkallread.'" class="iconsmall" /></a></span>';
                     } else {
                         $unreadlink = '<span class="read">0</span>';
                     }

mod/forum/lib.php+2 −2 modified

@@ -3913,7 +3913,7 @@ function forum_print_discussion_header(&$post, $forum, $group=-1, $datestring=""
                     echo $post->unread;
                     echo '</a>';
                     echo '<a title="'.$strmarkalldread.'" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php">' .
+                         $forum->id.'&amp;d='.$post->discussion.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">' .
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.$strmarkalldread.'" /></a>';
                     echo '</span>';
                 } else {
@@ -5824,7 +5824,7 @@ function forum_print_latest_discussions($course, $forum, $maxdiscussions=-1, $di
                 if ($forumtracked) {
                     echo '<a title="'.get_string('markallread', 'forum').
                          '" href="'.$CFG->wwwroot.'/mod/forum/markposts.php?f='.
-                         $forum->id.'&amp;mark=read&amp;returnpage=view.php">'.
+                         $forum->id.'&amp;mark=read&amp;returnpage=view.php&amp;sesskey=' . sesskey() . '">'.
                          '<img src="'.$OUTPUT->pix_url('t/markasread') . '" class="iconsmall" alt="'.get_string('markallread', 'forum').'" /></a>';
                 }
                 echo '</th>';

mod/forum/markposts.php+1 −0 modified

@@ -55,6 +55,7 @@
 $user = $USER;
 
 require_login($course, false, $cm);
+require_sesskey();
 
 if ($returnpage == 'index.php') {
     $returnto = forum_go_back_to($returnpage.'?id='.$course->id);

Vulnerability mechanics

Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

www.openwall.com/lists/oss-security/2016/05/17/4nvdMailing ListThird Party AdvisoryWEB
www.securityfocus.com/bid/91281nvdThird Party AdvisoryVDB Entry
www.securitytracker.com/id/1035902nvdThird Party AdvisoryVDB Entry
bugzilla.redhat.com/show_bug.cginvdIssue TrackingThird Party AdvisoryWEB
github.com/advisories/GHSA-r867-v437-4rrmghsaADVISORY
nvd.nist.gov/vuln/detail/CVE-2016-3734ghsaADVISORY
github.com/moodle/moodle/commit/01408d619ba89d32f9ad83308990ff9b0374cb57ghsaWEB
github.com/moodle/moodle/commit/1f5c494f761ef7961c449075adf192e149148e1aghsaWEB
github.com/moodle/moodle/commit/7873e36f0cc0ccfd1424ff9302eb1ea9e4e74305ghsaWEB
github.com/moodle/moodle/commit/d98c24659935c1bdff4b35ec0a85ab1a3ab05d9fghsaWEB
github.com/moodle/moodle/commit/e90e0ea5700ee9b016034b74ed7f41787109d1a2ghsaWEB
web.archive.org/web/20160703032310/http://www.securitytracker.com/id/1035902ghsaWEB
web.archive.org/web/20160930194927/http://www.securityfocus.com/bid/91281ghsaWEB

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cvss	0.572
epss	0.000
exploit	0.000
kev	0.000
patch	-0.070
ransomware	0.000