CVE-2021-20254
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering.
- Exploit odds
- 1.6% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 1.6% in the next 30 days (EPSS).
- Severity: 6.8 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 1.6% · EPSS, next 30 days
- Weakness
- CWE-125 · Out-of-bounds read
- Record status
- Modified
Affected
- Samba < 4.12.15
- Samba < 4.13.8
- Samba < 4.14.4
- Fedoraproject Fedora 32
- Fedoraproject Fedora 33
- Redhat Enterprise Linux 7.0
- Redhat Enterprise Linux 8.0
- Debian Linux 9.0
Attack profile CVSS 3.1 · 6.8
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-20254.md and follow it. Check whether this project is affected by CVE-2021-20254. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://www.samba.org/samba/security/CVE-2021-20254.html
- https://www.samba.org/samba/security/CVE-2021-20254.html
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1949442
- https://lists.debian.org/debian-lts-announce/2021/05/msg00023.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/
- https://security.gentoo.org/glsa/202105-22
- https://security.netapp.com/advisory/ntap-20210430-0001/
- https://www.samba.org/samba/security/CVE-2021-20254.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1949442
- https://lists.debian.org/debian-lts-announce/2021/05/msg00023.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/
- https://security.gentoo.org/glsa/202105-22
- https://security.netapp.com/advisory/ntap-20210430-0001/
- https://www.samba.org/samba/security/CVE-2021-20254.html