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Vulnerability · Published May 5, 2021 · Assigned by redhat

CVE-2021-20254

Medium 6.8

In plain English

A medium-severity out-of-bounds read in samba. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.6% (higher than 76% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)6.8Medium
Exploit odds (30 days)1.6%top 23.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8libsmbclient-devel4.13.3-5.el8_4ALSA-2021:4058
AlmaLinux:8libwbclient-devel4.13.3-5.el8_4ALSA-2021:4058
AlmaLinux:8samba-devel4.13.3-5.el8_4ALSA-2021:4058
Alpine:v3.20samba4.14.4-r0ALPINE-CVE-2021-20254
Alpine:v3.21samba4.14.4-r0ALPINE-CVE-2021-20254
Alpine:v3.22samba4.14.4-r0ALPINE-CVE-2021-20254
Alpine:v3.23samba4.14.4-r0ALPINE-CVE-2021-20254
Alpine:v3.24samba4.14.4-r0ALPINE-CVE-2021-20254
Debian:12samba2:4.13.5+dfsg-2DEBIAN-CVE-2021-20254
Debian:13samba2:4.13.5+dfsg-2DEBIAN-CVE-2021-20254
Debian:14samba2:4.13.5+dfsg-2DEBIAN-CVE-2021-20254
Rocky Linux:8samba0:4.13.3-5.el8_4RLSA-2021:4058

Affected products (as reported)

VendorProductVersions
n/a samba samba 4.14.1, samba 4.13.6, samba 4.12.13

Weakness: CWE-125

References