CVE-2026-49851

HIGHCVSS 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 73% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: adp:redhat-sadp, epss
Trending — 3 sources updated this weekElevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear (approximately O(n²)) behavior in parse_link_text. When parsing Markdown containing many consecutive [ characters, parse_link_text repeatedly scans the input using a regex search inside a loop. Each iteration re-scans a large portion of the remaining string, resulting in quadratic-time behavior. An attacker-controlled Markdown input can therefore trigger excessive CPU usage with a very small payload. This vulnerability is fixed in 3.3.0.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
27.1%
KEV
Not listed

Published

June 24, 2026

Last Modified

July 2, 2026

Advisory Details (1)

Auto-updated Jun 24, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Potential DoS via quadratic-time parsing in parse_link_text · Advisory · lepture/mistune · GitHub

https://github.com/lepture/mistune/security/advisories/GHSA-qcq2-496w-v96p

Vendor Advisories for CVE-2026-49851(1)

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

Weakness Classification(4)

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

Data Freshness Timeline

(refreshed 33× in last 7d / 53× 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. 2026-07-06 23:05 UTCEG score recompute
  2. 2026-07-06 23:05 UTCVendor advisory
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 11:38 UTCEG score recompute
  5. 2026-07-06 11:38 UTCVendor advisory
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-06 00:10 UTCEG score recompute
  8. 2026-07-06 00:10 UTCVendor advisory
  9. 2026-07-05 12:44 UTCEG score recompute
  10. 2026-07-05 12:44 UTCVendor advisory
  11. 2026-07-05 02:30 UTCEPSS rescore
  12. 2026-07-05 01:16 UTCEG score recompute
  13. 2026-07-05 01:16 UTCVendor advisory
  14. 2026-07-04 13:37 UTCEG score recompute
  15. 2026-07-04 13:37 UTCVendor advisory
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-04 02:08 UTCEG score recompute
  18. 2026-07-04 02:08 UTCVendor advisory
  19. 2026-07-03 14:40 UTCEG score recompute
  20. 2026-07-03 14:40 UTCVendor advisory
  21. 2026-07-03 03:13 UTCEG score recompute
  22. 2026-07-03 03:13 UTCVendor advisory
  23. 2026-07-02 15:48 UTCEG score recompute
  24. 2026-07-02 15:48 UTCVendor advisory
  25. 2026-07-02 04:21 UTCEG score recompute
Show 28 more
  1. 2026-07-02 04:21 UTCVendor advisory
  2. 2026-07-01 16:55 UTCEG score recompute
  3. 2026-07-01 16:55 UTCVendor advisory
  4. 2026-07-01 15:07 UTCEPSS rescore
  5. 2026-07-01 05:29 UTCEG score recompute
  6. 2026-06-30 23:22 UTCEPSS rescore
  7. 2026-06-30 18:03 UTCEG score recompute
  8. 2026-06-30 06:37 UTCEG score recompute▼ 1.20
  9. 2026-06-30 04:34 UTCNVD updateCVSS v3 → 7.5
  10. 2026-06-29 19:10 UTCEG score recompute
  11. 2026-06-29 14:06 UTCEPSS rescore
  12. 2026-06-29 14:06 UTCEPSS rescore
  13. 2026-06-29 07:44 UTCEG score recompute
  14. 2026-06-28 20:12 UTCEG score recompute
  15. 2026-06-28 14:07 UTCEPSS rescore
  16. 2026-06-28 08:45 UTCEG score recompute
  17. 2026-06-28 04:56 UTCEPSS rescore
  18. 2026-06-28 04:56 UTCEPSS rescore
  19. 2026-06-27 21:19 UTCEG score recompute
  20. 2026-06-27 09:53 UTCEG score recompute
  21. 2026-06-27 03:08 UTCEPSS rescore
  22. 2026-06-26 22:27 UTCEG score recompute
  23. 2026-06-26 11:00 UTCEG score recompute
  24. 2026-06-25 18:58 UTCEG score recompute
  25. 2026-06-25 13:49 UTCEPSS rescore
  26. 2026-06-25 07:31 UTCEG score recompute
  27. 2026-06-24 20:05 UTCEG score recompute
  28. 2026-06-24 20:03 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-49851?
CVE-2026-49851 is a high vulnerability published on June 24, 2026. Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, Mistune is vulnerable to a CPU exhaustion DoS due to superlinear (approximately O(n²)) behavior in parselinktext. When parsing Markdown containing many consecutive [ characters, parselinktext repeatedly scans the input…
When was CVE-2026-49851 disclosed?
CVE-2026-49851 was first published in the National Vulnerability Database on June 24, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49851 actively exploited?
CVE-2026-49851 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49851?
CVE-2026-49851 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-49851?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49851, 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.

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