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 a BLP container, and thus an attempted memory allocation can be very large.
CVE-2021-27921
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 38% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 86.5%
- KEV
- Not listed
Published
March 3, 2021
Last Modified
August 15, 2025
References (10)
- cve@mitrehttps://lists.fedoraproject.org/archives/list/[email protected]/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/
- cve@mitrehttps://lists.fedoraproject.org/archives/list/[email protected]/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/
- cve@mitrehttps://lists.fedoraproject.org/archives/list/[email protected]/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/
- cve@mitrehttps://pillow.readthedocs.io/en/stable/releasenotes/8.1.2.html
- cve@mitrehttps://security.gentoo.org/glsa/202107-33
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/
- af854a3a-2127-422b-91ae-364da2661108https://pillow.readthedocs.io/en/stable/releasenotes/8.1.1.html
- af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202107-33
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3-pil.imagetk (3.1.2-0ubuntu1.6) @ xenial | 2026-05-26 | ubuntu |
| redhat | python-pillow-0:5.1.1-16.el8 | 2021-11-09 | redhat |
| redhat | quay/quay-rhel8:v3.6.0-62 | 2021-10-19 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| pillow | 1.0 ... 8.1.0 (77 versions) | 8.1.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(3)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 10× in last 7d / 44× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:25 UTCEPSS rescore
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- 2026-05-26 20:14 UTCEG score recompute
- 2026-05-26 20:14 UTCVendor advisory
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-23 09:01 UTCOSV refresh
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- CVE-2002-2433EG 0.0NONE
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Frequently asked(5)
What is CVE-2021-27921?
When was CVE-2021-27921 disclosed?
Is CVE-2021-27921 actively exploited?
What is the CVSS score of CVE-2021-27921?
How do I remediate CVE-2021-27921?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-27921
Is Your Infrastructure Affected by CVE-2021-27921?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.