Skip to content
Fencer Vulns
medium 6.2

CVE-2021-33640 json

After tar_close(), libtar.c releases the memory pointed to by pointer t.

published 2022-12-19 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20317

cvss
6.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

After tar_close(), libtar.c releases the memory pointed to by pointer t. After tar_close() is called in the list() function, it continues to use pointer t: free_longlink_longname(t->th_buf) . As a result, the released memory is used (use-after-free).

Patch / fix

  • libtar openSUSE Tumbleweed 1.2.20-3.1

opensuse advisories openSUSE-SU-2026:11092-1

  • libtar CBL-Mariner 2.0, Azure Linux 3.0 1.2.20-11

azure linux advisories AZL-12933AZL-34950

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-33640 updated cvss 6.2

libtar: fixes for CVE-2021-33645 and CVE-2021-33646 introduced new use-after-free bugs in libtar

  • Red Hat Enterprise Linux 6 libtar Red Hat Enterprise Linux 7 libtar
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 libtar
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.2 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • openEuler openEuler 22.03 LTS
  • openEuler openEuler 20.03 LTS SP1
  • openEuler openEuler 20.03 LTS SP3

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.