CVE-2026-86433

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-07. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

September 7, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Sep 7, 2026
Patch available. Sources: github.
generic

commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes | Advisories | VulnCheck

https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.8.4-denial-of-service-via-attributes
github Patch Available

Denial of service via adjacent inline attribute blocks · Advisory · thephpleague/commonmark · GitHub

https://github.com/thephpleague/commonmark/security/advisories/GHSA-g2gp-3wwq-f4ph

Vendor Advisories for CVE-2026-86433(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.10.0-1 ... 2.9.0-1 (23 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.10.0-1 ... 2.9.0-1 (11 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
php-league-commonmark2.7.0-1 ... 2.8.3-1 (8 versions)2.9.0-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 26× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 04:27 UTCEG score recompute
  2. 2026-09-19 04:27 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 16:14 UTCGHSA enrichment
  5. 2026-09-18 03:24 UTCEG score recompute
  6. 2026-09-18 03:24 UTCGHSA enrichment
  7. 2026-09-17 19:32 UTCEPSS rescore
  8. 2026-09-17 15:11 UTCGHSA enrichment
  9. 2026-09-17 02:58 UTCGHSA enrichment
  10. 2026-09-16 14:13 UTCEG score recompute
  11. 2026-09-16 14:13 UTCGHSA enrichment
  12. 2026-09-16 14:09 UTCEPSS rescore
  13. 2026-09-16 05:15 UTCEPSS rescore
  14. 2026-09-16 02:00 UTCGHSA enrichment
  15. 2026-09-15 13:47 UTCEG score recompute
  16. 2026-09-15 13:47 UTCGHSA enrichment
  17. 2026-09-15 03:12 UTCEPSS rescore
  18. 2026-09-15 03:12 UTCEPSS rescore
  19. 2026-09-15 01:34 UTCGHSA enrichment
  20. 2026-09-14 13:21 UTCGHSA enrichment
  21. 2026-09-14 01:08 UTCEG score recompute
  22. 2026-09-14 01:08 UTCGHSA enrichment
  23. 2026-09-13 12:55 UTCGHSA enrichment
  24. 2026-09-13 00:42 UTCEG score recompute
  25. 2026-09-13 00:42 UTCGHSA enrichment
Show 24 more
  1. 2026-09-12 12:29 UTCGHSA enrichment
  2. 2026-09-12 00:16 UTCEG score recompute
  3. 2026-09-12 00:16 UTCGHSA enrichment
  4. 2026-09-11 14:53 UTCEPSS rescore
  5. 2026-09-11 14:53 UTCEPSS rescore
  6. 2026-09-11 12:03 UTCEG score recompute
  7. 2026-09-11 12:03 UTCGHSA enrichment
  8. 2026-09-10 23:50 UTCGHSA enrichment
  9. 2026-09-10 11:33 UTCEG score recompute
  10. 2026-09-10 11:32 UTCGHSA enrichment
  11. 2026-09-09 23:18 UTCGHSA enrichment
  12. 2026-09-09 08:25 UTCEG score recompute
  13. 2026-09-09 08:25 UTCGHSA enrichment
  14. 2026-09-08 22:01 UTCEPSS rescore
  15. 2026-09-08 20:13 UTCGHSA enrichment
  16. 2026-09-08 13:49 UTCEG score recompute
  17. 2026-09-08 13:48 UTCGHSA enrichment
  18. 2026-09-08 13:03 UTCEG score recompute
  19. 2026-09-08 13:03 UTCGHSA enrichment
  20. 2026-09-08 01:41 UTCEG score recompute
  21. 2026-09-08 01:40 UTCGHSA enrichment
  22. 2026-09-07 13:28 UTCEG score recompute
  23. 2026-09-07 12:57 UTCEG score recompute
  24. 2026-09-07 12:56 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-86433?
CVE-2026-86433 is a high vulnerability published on September 7, 2026. commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks…
When was CVE-2026-86433 disclosed?
CVE-2026-86433 was first published in the National Vulnerability Database on September 7, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86433 actively exploited?
CVE-2026-86433 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 78.1% of all scored CVEs.
What is the CVSS score of CVE-2026-86433?
CVE-2026-86433 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-86433?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-86433, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-86433

Explore →

Is Your Infrastructure Affected by CVE-2026-86433?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs