CVE-2011-1089
Description
The addmntent function in the GNU C Library (aka glibc or libc6) 2.13 and earlier does not report an error status for failed attempts to write to the /etc/mtab file, which makes it easier for local users to trigger corruption of this file, as demonstrated by writes from a process with a small RLIMIT_FSIZE value, a different vulnerability than CVE-2010-0296.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
The addmntent function in glibc 2.13 and earlier fails to report write failures, allowing local users to corrupt /etc/mtab via RLIMIT_FSIZE.
Vulnerability
The addmntent function in the GNU C Library (glibc) versions 2.13 and earlier does not return an error status when a write to the /etc/mtab file fails [1][4]. The function uses fprintf and only returns failure if fprintf returns <0, but partial writes (e.g., due to RLIMIT_FSIZE) are not detected [4]. This affects all programs that call addmntent, particularly suid mount helpers such as those in util-linux, mount.cifs, and others [1].
Exploitation
A local attacker with the ability to set a small RLIMIT_FSIZE value (e.g., via ulimit) can cause a process writing to /etc/mtab to have its write truncated. If the process catches or ignores SIGXFSZ (as many suid helpers do), the write may be partial but addmntent returns success, leaving /etc/mtab in an inconsistent state [1][4]. The attacker does not need special privileges beyond the ability to set resource limits for a process they control.
Impact
Successful exploitation results in corruption of the /etc/mtab file, which can lead to incorrect mount information being reported. This may cause subsequent mount/umount operations to fail or behave unexpectedly, potentially leading to denial of service or further system instability [1]. The corruption is persistent until /etc/mtab is manually repaired.
Mitigation
Red Hat released RHSA-2011:1526 to address this issue in glibc [2]. The fix ensures that addmntent properly reports write failures. Users should update glibc to a patched version. As a workaround, replacing /etc/mtab with a symlink to /proc/mounts eliminates the need to write to /etc/mtab [3]. Note that CVE-2011-1089 is distinct from CVE-2010-0296.
AI Insight generated on May 23, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
59cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*+ 57 more
- cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*range: <=2.13
- cpe:2.3:a:gnu:glibc:1.00:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.01:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.02:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.03:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.04:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.05:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.06:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.07:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.08:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.09:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:1.09.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.4:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.5:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.0.6:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.10:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.10.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.10.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.11:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.11.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.11.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.11.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.1.6:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.12.0:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.12.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.12.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.3.10:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.1.9:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2.4:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.2.5:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.10:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.2:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.3:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.4:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.5:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.3.6:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.4:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.5:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.5.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.6:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.6.1:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.7:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.8:*:*:*:*:*:*:*
- cpe:2.3:a:gnu:glibc:2.9:*:*:*:*:*:*:*
- Range: <=2.13
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
22- openwall.com/lists/oss-security/2011/03/04/10nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/04/11nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/04/12nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/04/9nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/05/3nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/05/7nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/07/9nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/14/16nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/14/5nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/14/7nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/15/6nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/22/4nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/22/6nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/31/3nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/03/31/4nvdMailing ListThird Party Advisory
- openwall.com/lists/oss-security/2011/04/01/2nvdMailing ListThird Party Advisory
- www.redhat.com/support/errata/RHSA-2011-1526.htmlnvdThird Party Advisory
- www.securityfocus.com/bid/46740nvdThird Party AdvisoryVDB Entry
- sourceware.org/bugzilla/show_bug.cginvdIssue Tracking
- www.mandriva.com/security/advisoriesnvdBroken Link
- www.mandriva.com/security/advisoriesnvdBroken Link
- bugzilla.redhat.com/show_bug.cginvdIssue Tracking
News mentions
0No linked articles in our index yet.