Out-of-bounds Read in Samba
CVE-2021-20254
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.016 (75.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000
Affected products
- Samba
- Debian Linux — versions 9.0
- Fedoraproject Fedora — versions 32, 33
- Red Hat Enterprise Linux — versions 7.0, 8.0
- Samba — versions samba 4.14.1, samba 4.13.6, samba 4.12.13
Weakness classification (CWE)
References
- bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
- www.samba.org/samba/security/CVE-2021-20254.html (Vendor Advisory)
- security.netapp.com/advisory/ntap-20210430-0001/ (Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202105-22 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/05/msg00023.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-20254?
- CVE-2021-20254 is a medium-severity vulnerability in Samba, classified under Out-of-bounds Read. CVSS score: 6.8/10. Published 2021-05-05.
- How severe is CVE-2021-20254?
- Medium severity. CVSS v3 base score is 6.8 out of 10.