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Fencer Intel
medium 6.5

CVE-2021-25292 json

Regular Expression Denial of Service (ReDoS) in Pillow

published 5y ago modified 2mo ago also BIT-pillow-2021-25292 , EUVD-2021-0175 , GHSA-9hx2-hgq2-2g4f , PYSEC-2021-38

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

An issue was discovered in Pillow before 8.1.1. The PDF parser allows a regular expression DoS (ReDoS) attack via a crafted PDF file because of a catastrophic backtracking regex.

Patch / fix

  • pypi pillow 8.1.1
  • bitnami pillow 8.1.1
  • python pillow 8.1.1
  • pillow Debian 14, Debian 13, Debian 12 8.1.1-1

debian advisories DEBIAN-CVE-2021-25292

  • pillow Ubuntu 18.04 LTS 5.1.0-1ubuntu0.5
  • pillow Ubuntu 20.04 LTS 7.0.0-4ubuntu0.3

ubuntu advisories UBUNTU-CVE-2021-25292

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

  • python-pillow RHEL 8 5.1.1-16.el8
  • python3-pillow RHEL 8 5.1.1-16.el8

red hat advisories RHSA-2021:4149

  • python-Pillow SLE Module for Package Hub 15 SP6, openSUSE Leap 15.5 7.2.0-150300.3.15.1
  • python-Pillow OpenStack Cloud Crowbar 8, OpenStack Cloud 8, HPE Helion OpenStack 8 4.2.1-3.14.1
  • python-Pillow OpenStack Cloud Crowbar 9, OpenStack Cloud 9 5.2.0-3.8.1

suse advisories SUSE-SU-2024:1673-2SUSE-SU-2024:1673-1SUSE-SU-2021:1939-1SUSE-SU-2021:1938-1

  • python-Pillow openSUSE Tumbleweed 12.3.0-1.1
  • python-Pillow openSUSE Tumbleweed 8.3.2-1.2
  • python-Pillow openSUSE Tumbleweed 10.3.0-1.1
  • python-Pillow openSUSE Leap 15.2 8.3.1-lp152.5.3.1
  • python-CairoSVG openSUSE Leap 15.2 2.5.1-lp152.2.3.1

opensuse advisories openSUSE-SU-2026:11261-1openSUSE-SU-2024:11209-1openSUSE-SU-2024:13827-1openSUSE-SU-2021:1134-1

  • python3-pillow AlmaLinux 8 5.1.1-16.el8

almalinux advisories ALSA-2021:4149

  • python-pillow Rocky Linux 8 5.1.1-16.el8

rocky linux advisories RLSA-2021:4149

  • py3-pillow Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 8.1.2-r0

alpine advisories ALPINE-CVE-2021-25292

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

  • python-pillow Arch Linux 8.1.2-1

arch linux advisories AVG-1635

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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-2021-25292 updated cvss 7.5

python-pillow: Regular expression DoS in PDF format parser

  • Red Hat Enterprise Linux 7 python-pillow, python-pillow-qt, python-pillow-tk, python-pillow-sane
    affected: workaround, no fix planned “Disable the invoice generation feature to mitigate this vulnerability in Red Hat Quay.”
  • Red Hat Enterprise Linux 9 python-pillow
    affected: workaround, no fix available “Disable the invoice generation feature to mitigate this vulnerability in Red Hat Quay.”
  • Red Hat Quay v3 quay/quay-rhel8 v3.6.0-62
    fixed: vendor fix “Disable the invoice generation feature to mitigate this vulnerability in Red Hat Quay.” RHSA-2021:3917
  • Red Hat Enterprise Linux AppStream (v. 8) python-pillow 5.1.1-16.el8, python3-pillow 5.1.1-16.el8
    fixed: vendor fix “Disable the invoice generation feature to mitigate this vulnerability in Red Hat Quay.” RHSA-2021:4149
  • Red Hat Quay v3 quay/clair-rhel8 v3.6.0-70, quay/quay-builder-rhel8 v3.6.0-44, quay/quay-operator-rhel8 v3.6.0-43, quay/quay-operator-bundle v3.6.0-48, quay/quay-bridge-operator-rhel8 v3.6.0-40, quay/quay-bridge-operator-bundle v3.6.0-35, +3 more
    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

Exploit prediction

1.73% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi pillow
>=5.1.0, <8.1.1
<8.1.1
8.1.1
bitnami pillow
<8.1.1
8.1.1

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel 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.