CVE-2026-49851

HIGHPre-NVD 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: 0.3%, 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: epss, secondary
Trending — 3 sources updated this weekElevated
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: Elevated riskExposed: 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)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

June 24, 2026

Last Modified

July 15, 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(2)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
mistune0.1.0 ... 3.2.1 (51 versions)3.3.0—

Weakness Classification(4)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 69× 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. 2026-07-27 02:54 UTCVendor advisory
  2. 2026-07-26 15:26 UTCEG score recompute
  3. 2026-07-26 15:26 UTCVendor advisory
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-25 14:18 UTCEPSS rescore
  6. 2026-07-24 14:18 UTCEPSS rescore
  7. 2026-07-23 14:18 UTCEPSS rescore
  8. 2026-07-23 03:18 UTCEG score recompute
  9. 2026-07-22 14:08 UTCEPSS rescore
  10. 2026-07-20 17:08 UTCEPSS rescore
  11. 2026-07-19 14:31 UTCEPSS rescore
  12. 2026-07-19 14:31 UTCEPSS rescore
  13. 2026-07-19 02:29 UTCEPSS rescore
  14. 2026-07-18 10:04 UTCEPSS rescore
  15. 2026-07-17 00:18 UTCVendor advisory
  16. 2026-07-16 17:03 UTCEPSS rescore
  17. 2026-07-16 12:52 UTCVendor advisory
  18. 2026-07-16 01:25 UTCVendor advisory
  19. 2026-07-15 16:57 UTCEPSS rescore
  20. 2026-07-15 16:57 UTCEPSS rescore
  21. 2026-07-15 13:59 UTCVendor advisory
  22. 2026-07-15 02:00 UTCEPSS rescore
  23. 2026-07-14 14:38 UTCVendor advisory
  24. 2026-07-14 03:11 UTCVendor advisory
  25. 2026-07-13 22:30 UTCEPSS rescore
Show 48 more
  1. 2026-07-13 06:13 UTCEPSS rescore
  2. 2026-07-13 04:18 UTCVendor advisory
  3. 2026-07-12 16:49 UTCVendor advisory
  4. 2026-07-12 05:46 UTCEPSS rescore
  5. 2026-07-12 05:22 UTCVendor advisory
  6. 2026-07-11 17:56 UTCVendor advisory
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-11 06:30 UTCVendor advisory
  9. 2026-07-10 19:04 UTCVendor advisory
  10. 2026-07-10 07:38 UTCVendor advisory
  11. 2026-07-09 20:12 UTCVendor advisory
  12. 2026-07-09 19:10 UTCEPSS rescore
  13. 2026-07-09 08:45 UTCVendor advisory
  14. 2026-07-08 21:19 UTCVendor advisory
  15. 2026-07-08 15:16 UTCEPSS rescore
  16. 2026-07-08 09:51 UTCVendor advisory
  17. 2026-07-07 22:25 UTCVendor advisory
  18. 2026-07-07 13:46 UTCEPSS rescore
  19. 2026-07-07 11:00 UTCVendor advisory
  20. 2026-07-06 23:05 UTCVendor advisory
  21. 2026-07-06 16:27 UTCEPSS rescore
  22. 2026-07-06 11:38 UTCVendor advisory
  23. 2026-07-06 02:23 UTCEPSS rescore
  24. 2026-07-06 00:10 UTCVendor advisory
  25. 2026-07-05 12:44 UTCVendor advisory
  26. 2026-07-05 02:30 UTCEPSS rescore
  27. 2026-07-05 01:16 UTCVendor advisory
  28. 2026-07-04 13:37 UTCVendor advisory
  29. 2026-07-04 06:31 UTCEPSS rescore
  30. 2026-07-04 02:08 UTCVendor advisory
  31. 2026-07-03 14:40 UTCVendor advisory
  32. 2026-07-03 03:13 UTCVendor advisory
  33. 2026-07-02 15:48 UTCVendor advisory
  34. 2026-07-02 04:21 UTCVendor advisory
  35. 2026-07-01 16:55 UTCVendor advisory
  36. 2026-07-01 15:07 UTCEPSS rescore
  37. 2026-06-30 23:22 UTCEPSS rescore
  38. 2026-06-30 06:37 UTCEG score recompute▼ 1.20
  39. 2026-06-30 04:34 UTCNVD updateCVSS v3 → 7.5
  40. 2026-06-29 14:06 UTCEPSS rescore
  41. 2026-06-29 14:06 UTCEPSS rescore
  42. 2026-06-28 14:07 UTCEPSS rescore
  43. 2026-06-28 04:56 UTCEPSS rescore
  44. 2026-06-28 04:56 UTCEPSS rescore
  45. 2026-06-27 03:08 UTCEPSS rescore
  46. 2026-06-25 13:49 UTCEPSS rescore
  47. 2026-06-24 20:05 UTCEG score recompute
  48. 2026-06-24 20:03 UTCNVD updatefirst tracked

Related CVEs(same vendor + same CWE)

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 15, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 72.9% of all scored CVEs.
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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49851

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