Medium severity6.8NVD Advisory· Published May 5, 2021· Updated Jun 17, 2026
CVE-2021-20254
CVE-2021-20254
Description
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
58(expand)+ 1 more
- (no CPE)
- cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*range: >=3.6.0,<4.12.15
- osv-coords50 versionspkg:rpm/opensuse/samba&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/samba&distro=openSUSE%20Leap%2015.3pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Python%202%2015%20SP2pkg:rpm/suse/samba-doc&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2012%20SP4pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP3pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2012%20SP5pkg:rpm/suse/samba&distro=SUSE%20Enterprise%20Storage%207pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP2pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015pkg:rpm/suse/samba&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/samba&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP1pkg:rpm/suse/samba&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/almalinux/libsmbclient-develpkg:rpm/almalinux/libwbclient-develpkg:rpm/almalinux/samba-develpkg:rpm/suse/ldb&distro=SUSE%20Enterprise%20Storage%207pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2012%20SP3pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/samba&distro=SUSE%20Manager%20Retail%20Branch%20Server%204.0pkg:rpm/suse/samba&distro=SUSE%20Manager%20Server%204.0pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-ESPOSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Point%20of%20Sale%2011%20SP3pkg:rpm/suse/samba-doc&distro=SUSE%20Linux%20Enterprise%20Point%20of%20Sale%2011%20SP3pkg:rpm/suse/samba&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/suse/samba&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/samba&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2015-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/samba&distro=SUSE%20Manager%20Proxy%204.0pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Python%202%2015%20SP3pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20High%20Availability%20Extension%2015%20SP3pkg:rpm/opensuse/samba&distro=openSUSE%20Leap%2015.2pkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/samba&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCL
< 4.14.6+git.182.2205d5224e3-1.1+ 49 more
- (no CPE)range: < 4.14.6+git.182.2205d5224e3-1.1
- (no CPE)range: < 4.13.6+git.211.555d60b24ba-3.7.1
- (no CPE)range: < 4.11.14+git.247.8c858f7ee14-4.19.1
- (no CPE)range: < 3.6.3-94.34.1
- (no CPE)range: < 4.10.18+git.269.dd608524c88-3.27.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.13.6+git.211.555d60b24ba-3.7.1
- (no CPE)range: < 4.10.18+git.269.dd608524c88-3.27.1
- (no CPE)range: < 4.13.6+git.211.555d60b24ba-3.9.1
- (no CPE)range: < 4.11.14+git.247.8c858f7ee14-4.19.1
- (no CPE)range: < 4.7.11+git.316.432f0218290-4.54.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.13.3-5.el8_4
- (no CPE)range: < 4.13.3-5.el8_4
- (no CPE)range: < 4.13.3-5.el8_4
- (no CPE)range: < 2.2.1-4.3.1
- (no CPE)range: < 4.10.18+git.269.dd608524c88-3.27.1
- (no CPE)range: < 4.7.11+git.316.432f0218290-4.54.1
- (no CPE)range: < 3.6.3-94.34.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.10.18+git.269.dd608524c88-3.27.1
- (no CPE)range: < 4.11.14+git.247.8c858f7ee14-4.19.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.7.11+git.316.432f0218290-4.54.1
- (no CPE)range: < 3.6.3-94.34.1
- (no CPE)range: < 3.6.3-94.34.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.7.11+git.316.432f0218290-4.54.1
- (no CPE)range: < 4.7.11+git.316.432f0218290-4.54.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.9.5+git.432.d9b18c4f390-3.50.1
- (no CPE)range: < 4.13.6+git.211.555d60b24ba-3.7.1
- (no CPE)range: < 4.13.6+git.211.555d60b24ba-3.7.1
- (no CPE)range: < 4.11.14+git.247.8c858f7ee14-lp152.3.19.1
- (no CPE)range: < 4.6.16+git.282.cfafed5922a-3.61.1
- (no CPE)range: < 4.4.2-38.42.1
- Samba/Sambadescription
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
Patches
Vulnerability mechanics
References
7- bugzilla.redhat.com/show_bug.cginvdIssue TrackingThird Party Advisory
- lists.debian.org/debian-lts-announce/2021/05/msg00023.htmlnvdMailing ListThird Party Advisory
- security.gentoo.org/glsa/202105-22nvdThird Party Advisory
- security.netapp.com/advisory/ntap-20210430-0001/nvdThird Party Advisory
- www.samba.org/samba/security/CVE-2021-20254.htmlnvdVendor Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/nvd
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/nvd
News mentions
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