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TI-2026-59140 Aliases CVE-2026-86432GHSA-f58g-hmv8-g97m

commonmark 2.0.0 before 2.8.4 Denial of Service via XML

Priority LOW 37CWE-405Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

commonmark versions from 2.0.0 before 2.8.4 contain a denial of service vulnerability in XmlRenderer that emits depth-proportional indentation for every XML tag. Attackers can provide deeply nested Markdown or AST structures to cause quadratic memory consumption and output amplification, exhausting server resources.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00418 36th percentileScored 2026-11-07
Fix Fixed commonmark (thephpleague): 2.8.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
thephpleaguecommonmark2.0.0 to before 2.8.42.8.4Patch availableCNA
  • commonmark Vendorthephpleague Affected 2.0.0 to before 2.8.4 Fixed in 2.8.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:*——thephpleague
  • cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* Versions — — ·thephpleague

Remediation

  • Fix · CNA commonmark (thephpleague) Fixed in 2.8.4

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    thephpleague commonmark 2.8.4

    4 records Highest priority Priority MEDIUM 3 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-59143 commonmark 1.5.0 before 2.8.4 Denial of Service via FootnotePriority MEDIUM 44
    • TI-2026-59142 commonmark 2.0.0 through 2.8.3 Denial of Service via Slug CollisionPriority MEDIUM 44
    • TI-2026-59141 commonmark 1.5.0 before 2.8.4 Denial of Service via AttributesPriority MEDIUM 44
    Show all 4 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-86432
  2. 2026-10-03 Alias added: GHSA-f58g-hmv8-g97m

References

Advisory 1

  • TI-2026-69535 league/commonmark Quadratic DoS via TableStartParser CVSS 4.0HIGH 8.7
  • TI-2026-50093 league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes CVSS 3.1MEDIUM 6.1
  • TI-2026-69534 Cross-site scripting in League CommonMark bypasses DisallowedRawHtml CVSS 4.0MEDIUM 5.3
  • TI-2026-65445 Flysystem: WhitespacePathNormalizer's control-character (CorruptedPathDetected) check is… CVSS 3.1LOW 3.5
  • TI-2021-12376 Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem CVSS 3.1CRITICAL 9.8
  • TI-2026-59143 commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote CVSS 4.0HIGH 8.7
See all 20 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences