CVE-2026-33079

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: 0.5%, top 58% 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: 1%CVSS: 7.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

In versions 3.0.0a1 through 3.2.0 of Mistune, there is a ReDoS (Regular Expression Denial of Service) vulnerability in LINK_TITLE_RE that allows an attacker who can supply Markdown for parsing to cause denial of service. The regular expression used for parsing link titles contains overlapping alternatives that can trigger catastrophic backtracking. In both the double-quoted and single-quoted branches, a backslash followed by punctuation can be matched either as an escaped punctuation sequence or as two ordinary characters, creating an ambiguous pattern inside a repeated group. If an attacker supplies Markdown containing repeated ! sequences with no closing quote, the regex engine explores an exponential number of backtracking paths. This is reachable through normal Markdown parsing of inline links and block link reference definitions. A small crafted input can therefore cause significant CPU consumption and make applications using Mistune unresponsive.

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
1%
EPSS %ILE
42%
KEV
Not listed

Published

May 6, 2026

Last Modified

July 22, 2026

Advisory Details (2)

Auto-updated May 6, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

ReDoS in LINK_TITLE_RE allows denial of service via crafted Markdown input · Advisory · lepture/mistune · GitHub

https://github.com/lepture/mistune/security/advisories/GHSA-8mp2-v27r-99xp
generic

mistune/src/mistune/helpers.py at df23edd60b43b639d2e6760ef9dd3d618aa11c21 · lepture/mistune · GitHub

https://github.com/lepture/mistune/blob/df23edd60b43b639d2e6760ef9dd3d618aa11c21/src/mistune/helpers.py#L20-L25

Vendor Advisories for CVE-2026-33079(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatmta/mta-solution-server-rhel9:17841098832026-07-21redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
mistune3.1.3-1, 3.1.4-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
mistune3.1.3-1, 3.1.4-1——
PyPI(1)
PackageVulnerable rangeFixed inDependents
mistune3.0.0 ... 3.2.0 (17 versions)3.2.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 61× 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.

Showing the most recent 100 of 191 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 14:17 UTCEPSS rescore
  3. 2026-08-23 19:47 UTCEG score recompute
  4. 2026-08-23 19:47 UTCVendor advisory
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-21 23:49 UTCEPSS rescore
  7. 2026-08-20 22:55 UTCEPSS rescore
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-19 17:03 UTCEPSS rescore
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-17 13:47 UTCEPSS rescore
  12. 2026-08-17 12:52 UTCEG score recompute
  13. 2026-08-17 12:52 UTCVendor advisory
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 04:50 UTCEG score recompute
  16. 2026-08-16 04:50 UTCVendor advisory
  17. 2026-08-16 02:14 UTCEPSS rescore
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 15:45 UTCVendor advisory
  20. 2026-08-14 03:24 UTCEG score recompute
  21. 2026-08-14 03:24 UTCVendor advisory
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-13 06:06 UTCVendor advisory
  24. 2026-08-12 16:59 UTCEG score recompute
  25. 2026-08-12 16:59 UTCVendor advisory
Show 75 more
  1. 2026-08-12 13:50 UTCEPSS rescore
  2. 2026-08-11 15:59 UTCEG score recompute
  3. 2026-08-11 15:59 UTCVendor advisory
  4. 2026-08-11 01:30 UTCEG score recompute
  5. 2026-08-11 01:30 UTCVendor advisory
  6. 2026-08-11 00:00 UTCEPSS rescore
  7. 2026-08-10 03:16 UTCVendor advisory
  8. 2026-08-09 14:54 UTCEG score recompute
  9. 2026-08-09 14:54 UTCVendor advisory
  10. 2026-08-09 13:46 UTCEPSS rescore
  11. 2026-08-09 02:33 UTCEG score recompute
  12. 2026-08-09 02:33 UTCVendor advisory
  13. 2026-08-08 16:37 UTCEPSS rescore
  14. 2026-08-08 02:36 UTCEG score recompute
  15. 2026-08-08 02:36 UTCVendor advisory
  16. 2026-08-07 14:15 UTCVendor advisory
  17. 2026-08-07 01:53 UTCEG score recompute
  18. 2026-08-07 01:53 UTCVendor advisory
  19. 2026-08-06 13:46 UTCEPSS rescore
  20. 2026-08-06 10:49 UTCVendor advisory
  21. 2026-08-05 22:19 UTCEG score recompute
  22. 2026-08-05 22:19 UTCVendor advisory
  23. 2026-08-05 19:17 UTCEPSS rescore
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:38 UTCEPSS rescore
  26. 2026-08-03 19:50 UTCEG score recompute
  27. 2026-08-03 19:50 UTCVendor advisory
  28. 2026-08-03 10:36 UTCEPSS rescore
  29. 2026-08-02 17:23 UTCVendor advisory
  30. 2026-08-02 05:02 UTCEG score recompute
  31. 2026-08-02 05:02 UTCVendor advisory
  32. 2026-08-02 02:27 UTCEPSS rescore
  33. 2026-08-01 04:16 UTCEPSS rescore
  34. 2026-07-30 16:28 UTCEPSS rescore
  35. 2026-07-30 01:30 UTCEPSS rescore
  36. 2026-07-27 14:13 UTCEPSS rescore
  37. 2026-07-26 14:54 UTCEPSS rescore
  38. 2026-07-26 14:54 UTCEPSS rescore
  39. 2026-07-25 14:18 UTCEPSS rescore
  40. 2026-07-25 14:18 UTCEPSS rescore
  41. 2026-07-24 14:17 UTCEPSS rescore
  42. 2026-07-24 14:17 UTCEPSS rescore
  43. 2026-07-23 14:18 UTCEPSS rescore
  44. 2026-07-23 14:18 UTCEPSS rescore
  45. 2026-07-23 03:09 UTCEG score recompute▼ 1.20
  46. 2026-07-22 14:08 UTCEPSS rescore
  47. 2026-07-21 15:24 UTCEPSS rescore
  48. 2026-07-20 17:08 UTCEPSS rescore
  49. 2026-07-20 08:32 UTCOSV refresh
  50. 2026-07-19 02:29 UTCEPSS rescore
  51. 2026-07-18 10:04 UTCEPSS rescore
  52. 2026-07-18 10:04 UTCEPSS rescore
  53. 2026-07-16 17:03 UTCEPSS rescore
  54. 2026-07-16 17:03 UTCEPSS rescore
  55. 2026-07-15 16:57 UTCEPSS rescore
  56. 2026-07-15 16:57 UTCEPSS rescore
  57. 2026-07-15 02:00 UTCEPSS rescore
  58. 2026-07-15 02:00 UTCEPSS rescore
  59. 2026-07-13 22:30 UTCEPSS rescore
  60. 2026-07-13 06:13 UTCEPSS rescore
  61. 2026-07-13 06:13 UTCEPSS rescore
  62. 2026-07-12 05:46 UTCEPSS rescore
  63. 2026-07-11 08:27 UTCEPSS rescore
  64. 2026-07-09 19:10 UTCEPSS rescore
  65. 2026-07-08 15:15 UTCEPSS rescore
  66. 2026-07-07 13:46 UTCEPSS rescore
  67. 2026-07-06 02:23 UTCEPSS rescore
  68. 2026-07-06 02:23 UTCEPSS rescore
  69. 2026-07-05 02:30 UTCEPSS rescore
  70. 2026-07-04 06:31 UTCEPSS rescore
  71. 2026-07-01 15:06 UTCEPSS rescore
  72. 2026-06-30 23:22 UTCEPSS rescore
  73. 2026-06-30 04:33 UTCNVD updateCVSS v3 → 7.5
  74. 2026-06-29 14:06 UTCEPSS rescore
  75. 2026-06-29 14:06 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-33079?
CVE-2026-33079 is a high vulnerability published on May 6, 2026. In versions 3.0.0a1 through 3.2.0 of Mistune, there is a ReDoS (Regular Expression Denial of Service) vulnerability in LINKTITLERE that allows an attacker who can supply Markdown for parsing to cause denial of service. The regular expression used for parsing link titles contains overlapping…
When was CVE-2026-33079 disclosed?
CVE-2026-33079 was first published in the National Vulnerability Database on May 6, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33079 actively exploited?
CVE-2026-33079 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 58.4% of all scored CVEs.
What is the CVSS score of CVE-2026-33079?
CVE-2026-33079 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-33079?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33079, 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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