CVE-2021-27922

Pillow before 8.1.2 allows attackers to cause a denial of service (memory consumption) because the reported size of a contained image is not properly checked for an ICNS container, and thus an attempted memory allocation can be very large.

Published: 2021-03-03 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-27922 is rated High Risk (66.4/100): CVSS High severity, with high exploitation likelihood (EPSS 4.85%, 91th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +4.58% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

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-2021-27922

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 2026-06-15 0.28% 4.85% +4.58%
2 2026-04-20 0.14% 0.28% +0.13%
3 2025-12-24 0.14%

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27922

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/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:L)
Exploitation conditions are straightforward and predictable.
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.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-27922

GitHub Security Advisory for CVE-2021-27922

GHSA-3wvg-mj6g-m9cv · Severity: high · Ecosystem: pip — Pillow Uncontrolled Resource Consumption

OS Trackers for CVE-2021-27922

vendor priority summary link
alpine CVE-2021-27922: 1 source package rows (py3-pillow); 8 state rows across 8 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2021-27922
debian not yet assigned CVE-2021-27922 not yet assigned priority: Debian including 1 source packages (pillow), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-27922
gentoo normal CVE-2021-27922: 1 GLSA(s) (202107-33), 1 atom(s) (dev-python/pillow); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-27922
redhat medium https://access.redhat.com/security/cve/CVE-2021-27922
suse high CVE-2021-27922 severity important: SUSE including 16 source package names (python-Pillow, python-Pillow-2.8.1-4.22.1, …), 41 product×package rows across 20 product lines (HPE Helion OpenStack 8, SUSE Liberty Linux 8, … (20 product lines)): Known Not Affected 21, Fixed 20. https://www.suse.com/security/cve/CVE-2021-27922/
ubuntu medium CVE-2021-27922 medium priority: Ubuntu including 3 source packages (pillow, pillow-python2, python-imaging), 48 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 28, not-affected 11, released 5, ignored 2, needs-triage 2. https://ubuntu.com/security/CVE-2021-27922

Affected software / configurations for CVE-2021-27922

Vendor Product Version Raw CPE
python pillow < 8.1.1 cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

References for CVE-2021-27922

URL Tags
https://lists.fedoraproject.org/archives/list/[email protected]/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/
https://lists.fedoraproject.org/archives/list/[email protected]/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/
https://lists.fedoraproject.org/archives/list/[email protected]/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/
https://pillow.readthedocs.io/en/stable/releasenotes/8.1.2.html
https://security.gentoo.org/glsa/202107-33 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/
https://pillow.readthedocs.io/en/stable/releasenotes/8.1.1.html Release Notes Vendor Advisory
cvelogic Threat Intelligence