CVE-2021-20193

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.

Published: 2021-03-26 Last update: 2025-05-05 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20193 is rated Low Risk (20.4/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.07%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20193

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.30% 0.07% -0.23%
2 2025-11-18 0.07% 0.30% +0.23%
3 2025-03-30 — 0.07% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20193

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.3 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 1.8 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-20193

OS Trackers for CVE-2021-20193

vendor priority summary link
alpine — CVE-2021-20193: 1 source package rows (tar); 20 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 10. https://security.alpinelinux.org/vuln/CVE-2021-20193
debian unimportant CVE-2021-20193 unimportant priority: Debian including 1 source packages (tar), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-20193
gentoo low CVE-2021-20193: 1 GLSA(s) (202105-29), 1 atom(s) (app-arch/tar); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-20193
redhat medium — https://access.redhat.com/security/cve/CVE-2021-20193
suse medium CVE-2021-20193 severity moderate: SUSE including 310 source package names (0.23.1-12.3:tar-1.34-150000.3.12.1, 0.45.0.7.7.1:tar-1.30-3.6.1, …), 675 product×package rows across 397 product lines (Container bci/bci-sle15-kernel-module-devel, Container bci/kiwi, … (397 product lines)): Fixed 541, Known Affected 134. https://www.suse.com/security/cve/CVE-2021-20193/
ubuntu low CVE-2021-20193 low priority: Ubuntu including 1 source packages (tar), 11 status rows across 11 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): released 10, ignored 1. https://ubuntu.com/security/CVE-2021-20193

Affected software / configurations for CVE-2021-20193

Vendor Product Version Raw CPE
gnu tar <= 1.33 cpe:2.3:a:gnu:tar:*:*:*:*:*:*:*:*

References for CVE-2021-20193

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1917565 Issue Tracking Patch Third Party Advisory
https://git.savannah.gnu.org/cgit/tar.git/commit/?id=d9d4435692150fa8ff68e1b1a473d187cc3fd777 Mailing List Patch Third Party Advisory
https://savannah.gnu.org/bugs/?59897 Issue Tracking Patch Vendor Advisory
https://security.gentoo.org/glsa/202105-29 Third Party Advisory
cvelogic Threat Intelligence