Vulnerability Report

CVE-2021-27921

Title: Python Pillow Denial of Service (DoS)

Denial of Service (DoS)

Proof Of Concept

No public PoC currently indexed for CVE-2021-27921.

CWE Category CWE-20
Published Date Mar 03, 2021
Modified Date Aug 15, 2025
Exploit Status Not Found
Score 7.5 CVSS v3.1
Exploit Probability (EPSS)
3.17%

Vulnerability Summary

CVE-2021-27921: 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.

Impacted Vendors

P
python 1

Reference Links

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 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 https://security.gentoo.org/glsa/202107-33
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:N/I:N/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-27921 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.