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Fencer Vulns
high 7.5

CVE-2022-34749 json

Mistune vulnerable to catastrophic backtracking

published 2022-07-25 4 y ago modified 2026-06-17 4 mo ago also GHSA-fw3v-x4f2-v673 , PYSEC-2022-237 , EUVD-2022-0155

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

In mistune through 2.0.2, support of inline markup is implemented by using regular expressions that can involve a high amount of backtracking on certain edge cases. This behavior is commonly named catastrophic backtracking.

Patch / fix

  • pypi mistune 2.0.3
  • mistune Debian 14, Debian 13, Debian 12 2.0.3-1

debian advisories DEBIAN-CVE-2022-34749

  • ceph ceph storage 8.1 2:19.2.1-331.el9cp
  • thrift ceph storage 8.1 0.20.0-4.el9cp
  • cephadm ceph storage 8.1 2:19.2.1-331.el9cp
  • librbd1 ceph storage 8.1 2:19.2.1-331.el9cp
  • librgw2 ceph storage 8.1 2:19.2.1-331.el9cp
  • rbd-nbd ceph storage 8.1 2:19.2.1-331.el9cp
  • ceph-mib ceph storage 8.1 2:19.2.1-331.el9cp
  • ceph-base ceph storage 8.1 2:19.2.1-331.el9cp

red hat advisories RHSA-2026:2711RHSA-2026:2769

  • python-mistune openSUSE Tumbleweed 3.1.0-1.1

opensuse advisories openSUSE-SU-2025:14637-1

  • py3-mistune Alpine 3.24, Alpine 3.23, Alpine 3.22 +6 more 2.0.3-r0

alpine advisories ALPINE-CVE-2022-34749

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-mistune CBL-Mariner 2.0 0.8.3-5

azure linux advisories AZL-10403

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2022-34749 updated cvss 7.5

mistune: catastrophic backtracking

  • Red Hat Ceph Storage 6 python-mistune
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 4 python-mistune
    affected: no fix available
  • Red Hat Ceph Storage 7.1 Tools ceph 18.2.1-381.el8cp, ceph 18.2.1-381.el9cp, cephadm 18.2.1-381.el9cp, librbd1 18.2.1-381.el8cp, librbd1 18.2.1-381.el9cp, librgw2 18.2.1-381.el8cp, +37 more
    fixed: vendor fix RHSA-2026:2769
  • Red Hat Ceph Storage 8 rhceph 1770630907
    fixed: vendor fix RHSA-2026:2737
  • Red Hat Ceph Storage 8.1 Tools ceph 19.2.1-331.el9cp, cephadm 19.2.1-331.el9cp, librbd1 19.2.1-331.el9cp, librgw2 19.2.1-331.el9cp, rbd-nbd 19.2.1-331.el9cp, ceph-mib 19.2.1-331.el9cp, +17 more
    fixed: vendor fix RHSA-2026:2711
  • Red Hat Ceph Storage 8 rhceph 1770630607, rhceph 1770631713, rhceph 1770631941, rhceph 1770632172, rhceph 1770632233 Red Hat Ceph Storage 8.1 Tools thrift 0.20.0-4.el9cp, libarrow 9.0.0-11.el9cp, thrift-qt 0.20.0-4.el9cp, perl-thrift 0.20.0-4.el9cp, thrift-glib 0.20.0-4.el9cp, parquet-libs 9.0.0-11.el9cp, +7 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

1.62% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Affected packages

ecosystem package affected fixed in
pypi mistune
>=2.0.0a1, <2.0.3
2.0.3

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns 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.