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Fencer Vulns
low 3.3

CVE-2021-20193 json

A flaw was found in the src/list.c of tar 1.33 and earlier.

published 2021-03-26 5 y ago modified 2026-10-14 25 d ago also EUVD-2021-7640 , JLSEC-2026-183

cvss
3.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

A flaw was found in the src/list.c of tar 1.33 and earlier. This flaw allows an attacker who can submit a crafted input file to tar to cause uncontrolled consumption of memory. The highest threat from this vulnerability is to system availability.

Patch / fix

  • julia Tar_jll 1.34.0+0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • tar Debian 14, Debian 13, Debian 12 1.34+dfsg-1

debian advisories DEBIAN-CVE-2021-20193

  • tar Ubuntu 18.04 LTS 1.29b-2ubuntu0.3
  • tar Ubuntu 20.04 LTS 1.30+dfsg-7ubuntu0.20.04.2
  • tar Ubuntu 22.04 LTS 1.34+dfsg-1build1
  • tar Ubuntu Pro 14.04 LTS 1.27.1-1ubuntu0.1+esm2
  • tar Ubuntu Pro 16.04 LTS 1.28-2.1ubuntu0.2+esm1

ubuntu advisories UBUNTU-CVE-2021-20193

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tar SLE Real Time 15 SP2, SLE Module for Basesystem 15 SP3, SLE Micro 5.2 +3 more 1.34-150000.3.12.1
  • tar SLES for SAP 12 SP5, SLES 12 SP5 1.27.1-15.9.1
  • tar SLE Module for Basesystem 15 SP2, SLE Micro 5.0 1.30-3.6.1

suse advisories SUSE-SU-2022:1548-1SUSE-SU-2021:0975-1SUSE-SU-2021:0974-1

  • tar openSUSE Tumbleweed 1.34-5.1
  • tar openSUSE Leap 15.2 1.30-lp152.4.3.1

opensuse advisories openSUSE-SU-2024:11620-1openSUSE-SU-2021:0494-1

  • tar Alpine 3.10 1.32-r1
  • tar Alpine 3.12, Alpine 3.11 1.32-r2
  • tar Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 1.34-r0

alpine advisories ALPINE-CVE-2021-20193

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tar Arch Linux 1.34-1

arch linux advisories AVG-1462

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-2021-20193 updated cvss 3.3

tar: Memory leak in read_header() in list.c

  • Red Hat Enterprise Linux 6 tar Red Hat Enterprise Linux 7 tar
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 tar
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 tar
    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 ICSA-23-348-10 updated cvss 5.5

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
31 d ago

Exploit prediction

1.10% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
OSV 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
julia Tar_jll
<1.34.0+0
1.34.0+0

Affected products

  • n/a tar
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime
  • CWE-125 Out-of-bounds Read

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.