5.5

CVE-2021-46968: s390/zcrypt: fix zcard and zqueue hot-unplug memleak

Analyzed
AliasesUBUNTU-CVE-2021-46968DEBIAN-CVE-2021-46968
Published 27-02-2024Last modified 11-05-2026

Vulnerability summary

CVE-2021-46968 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.22%
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 2 · Related 2
SUSE-SU-2024:0856-1SUSE-SU-2024:0857-1

Timeline

  1. 27-02-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: fix zcard and zqueue hot-unplug memleak Tests with kvm and a kmemdebug kernel showed, that on hot unplug the zcard and zqueue structs for the unplugged card or queue are not properly freed because of a mismatch with get/put for the embedded kref counter. This fix now adjusts the handling of the kref counters. With init the kref counter starts with 1. This initial value needs to drop to zero with the unregister of the card or queue to trigger the release and free the object.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.22% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu62 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 29c2680fd2bf3862ff5cf2957f198512493156f9, < 026499a9c2e002e621ad568d1378324ae97e5524 | ≥ 29c2680fd2bf3862ff5cf2957f198512493156f9, < 055a063a18bcd19b93709e3eac8078d6b2f04599 | ≥ 29c2680fd2bf3862ff5cf2957f198512493156f9, < 971dc8706cee47393d393905d294ea47e39503d3 | ≥ 29c2680fd2bf3862ff5cf2957f198512493156f9, < 70fac8088cfad9f3b379c9082832b4d7532c16c2 | 5.10
  • linux_kernel≥ 5.10, < 5.10.36 | ≥ 5.11, < 5.11.20 | ≥ 5.12, < 5.12.3
Debian1 product
  • linux< 5.10.38-1

3 vendors · 65 products

References

8 links