6.8

CVE-2021-20254: debian debian_linux Out-of-bounds Read

Modified
AliasesALPINE-CVE-2021-20254SUSE-SU-2021:1438-1SUSE-SU-2021:1439-1
Published 05-05-2021Last modified 03-08-2024

Vulnerability summary

CVE-2021-20254 is a medium (CVSS 6.8) Out-of-bounds Read vulnerability in debian debian_linux. EPSS estimates a 1.62% chance of exploitation in the next 30 days, higher than 76% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.8, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.8/10
010
Medium · v3.1 (NVD)
EPSS score
1.62%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 12 · Related 9
DLA-2668-1MGASA-2021-0287OPENSUSE-SU-2021:0636-1OPENSUSE-SU-2021:3187-1OPENSUSE-SU-2024:11365-1RHSA-2021:3723

Timeline

  1. 05-05-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

1.62%

Chance of exploitation in the next 30 days

Percentile

76%

Versus all other CVEs

30-day change

No change 0.00 pp

From 1.62% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Redhat53 products
  • enterprise_linuxEOL7.0 | 8.0
  • ctdb< 0:4.10.16-15.el7_9 | < 0:4.14.5-201.el8rhgs | < 0:4.13.3-5.el8_4 | < 0:4.11.2-15.el8_2
  • ctdb-debuginfo< 0:4.14.5-201.el8rhgs | < 0:4.13.3-5.el8_4 | < 0:4.11.2-15.el8_2
  • ctdb-tests< 0:4.10.16-15.el7_9 | < 0:4.13.3-5.el8_4 | < 0:4.11.2-15.el8_2
  • ctdb-tests-debuginfo< 0:4.13.3-5.el8_4 | < 0:4.11.2-15.el8_2
Suse26 products
  • samba-doc&distro=SUSE Linux Enterprise Point of Sale 11 SP3< 3.6.3-94.34.1
  • samba-doc&distro=SUSE Linux Enterprise Server 11 SP4-LTSS< 3.6.3-94.34.1
  • samba&distro=HPE Helion OpenStack 8< 4.6.16+git.282.cfafed5922a-3.61.1
  • samba&distro=SUSE Linux Enterprise High Availability Extension 12 SP3< 4.6.16+git.282.cfafed5922a-3.61.1
  • samba&distro=SUSE Linux Enterprise High Availability Extension 12 SP4< 4.6.16+git.282.cfafed5922a-3.61.1
Debian2 products
Alpine1 product
  • samba≥ 3.6.0, < 4.12.15-r0 | ≥ 3.6.0, < 4.13.8-r0 | ≥ 3.6.0, < 4.14.4-r0
Fedoraproject1 product
Samba1 product
  • samba≥ 3.6.0, < 4.12.15 | ≥ 4.13.0, < 4.13.8 | ≥ 4.14.0, < 4.14.4
Ubuntu1 product
  • samba< 2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11 | < 2:4.3.11+dfsg-0ubuntu0.16.04.34 | < 2:4.7.6+dfsg~ubuntu-0ubuntu2.23 | < 2:4.11.6+dfsg-0ubuntu1.8

7 vendors · 85 products

References

40 links
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