Skip to main content
No exploitation reportedFix available

CVE-2026-59925

No exploitation reported by the sources we read.

  • Published2026-07-08
  • Fixed in3.3.0
  • WeaknessCWE-1333 · CWE-407

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences of well-formed double-asterisk or triple-asterisk emphasis pairs around a character cause quadratic work in src/mistune/inline_parser.py because the parser scans forward for matching close markers from every potential opening run, allowing denial of service in default Mistune parsing. This issue is fixed in version 3.3.0.

Timeline

dates in UTC
  1. 2026-07-0817:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-59925?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-59925?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Mistune project mistune
BranchAffectedFixed in
3.3< 3.3.03.3.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-59925 Red Hat Product Security25 known affected

    mistune: Mistune: Denial of Service via crafted Markdown input

    mta/mta-solution-server-rhel9 as a component of Migration Toolkit for Applications 8 · rhoai/odh-pipeline-runtime-datascience-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI) · rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI) · +22 more

Full record on NVD

Fix

  1. Update Mistune project mistune to 3.3.0
  2. Workaround from the vendor Red Hat Product Security CVE-2026-59925 · 25 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
  3. No fix available, says the vendor Red Hat Product Security CVE-2026-59925 · 25 productsFix deferred

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-07-08
Last Modified
2026-07-09
NVD status
Analyzed
GitHub Advisory
GHSA-4j32-57v6-6g45

Frequently asked questions

What is CVE-2026-59925?

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences of well-formed double-asterisk or triple-asterisk emphasis pairs around a character cause quadratic work in src/mistune/inline_parser.py because the parser scans forward for matching close markers from every potential opening run, allowing denial of service in default Mistune parsing. This issue is fixed in version 3.3.0.

Is CVE-2026-59925 actively exploited?

Active exploitation of CVE-2026-59925 has not been confirmed. Its EPSS score was 0.6% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-59925?

CVE-2026-59925 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running mistune? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, October 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database