CVE-2021-20254

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, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub advisories/code/issues, web search, more)
References	DLA-2668-1
Debian Bugs	987811

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
samba (PTS)	buster, buster (security)	2:4.9.5+dfsg-5+deb10u3	vulnerable
	bullseye (security), bullseye	2:4.13.13+dfsg-1~deb11u5	fixed
	bookworm, sid	2:4.17.6+dfsg-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
samba	source	stretch	2:4.5.16+dfsg-1+deb9u4		DLA-2668-1
samba	source	(unstable)	2:4.13.5+dfsg-2			987811

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)