| Name | 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-2668-1, ELA-422-1 |
| Debian Bugs | 987811 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| samba (PTS) | jessie, jessie (lts) | 2:4.2.14+dfsg-0+deb8u16 | fixed |
| stretch (security) | 2:4.5.16+dfsg-1+deb9u4 | fixed |
| stretch (lts), stretch | 2:4.5.16+dfsg-1+deb9u5 | fixed |
| buster (security), buster, buster (lts) | 2:4.9.5+dfsg-5+deb10u5 | vulnerable |
| bullseye (security), bullseye | 2:4.13.13+dfsg-1~deb11u6 | fixed |
| bookworm (security), bookworm | 2:4.17.12+dfsg-0+deb12u1 | fixed |
| sid, trixie | 2:4.21.1+dfsg-2 | fixed |
The information below is based on the following data on fixed versions.
Notes
[buster] - samba <no-dsa> (Minor issue)
https://www.samba.org/samba/security/CVE-2021-20254.html
https://bugzilla.samba.org/show_bug.cgi?id=14571
https://git.samba.org/?p=samba.git;a=commitdiff;h=75ad84167f5d2379557ec078d17c9a1c244402fc (master)