CVE-2026-80205

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-26. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
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.

NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic backtracking, resulting in indefinite CPU saturation and denial of service to all users of the Python process.

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
41%
KEV
Not listed

Published

August 26, 2026

Last Modified

September 3, 2026

Advisory Details (2)

Auto-updated Aug 26, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nltk-before-3.10.0-redos-via-text-findall-unvalidated-regex
github Patch Available🟡 PoC Available

ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions · Advisory · nltk/nltk · GitHub

https://github.com/nltk/nltk/security/advisories/GHSA-rrv8-h7p8-rx55

Vendor Advisories for CVE-2026-80205(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0-1 ... 3.9.3-1 (9 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0-1 ... 3.9.3-1 (6 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nltk3.9.1-2, 3.9.2-1, 3.9.3-13.10.0-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
nltk0.8 ... 3.9b1 (65 versions)3.10.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 75× 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 06:39 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 04:57 UTCEG score recompute
  4. 2026-09-16 14:17 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 05:15 UTCEPSS rescore
  7. 2026-09-15 12:35 UTCEG score recompute
  8. 2026-09-15 03:12 UTCEPSS rescore
  9. 2026-09-15 03:12 UTCEPSS rescore
  10. 2026-09-13 20:53 UTCEG score recompute
  11. 2026-09-12 19:11 UTCEG score recompute
  12. 2026-09-11 17:29 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-10 15:36 UTCEG score recompute
  16. 2026-09-09 00:52 UTCEG score recompute
  17. 2026-09-08 22:01 UTCEPSS rescore
  18. 2026-09-08 04:02 UTCEG score recompute
  19. 2026-09-08 04:02 UTCGHSA enrichment
  20. 2026-09-07 15:11 UTCGHSA enrichment
  21. 2026-09-07 00:07 UTCEG score recompute
  22. 2026-09-07 00:07 UTCGHSA enrichment
  23. 2026-09-06 13:48 UTCEPSS rescore
  24. 2026-09-06 11:14 UTCGHSA enrichment
  25. 2026-09-05 22:20 UTCEG score recompute
Show 50 more
  1. 2026-09-05 22:20 UTCGHSA enrichment
  2. 2026-09-05 15:31 UTCEPSS rescore
  3. 2026-09-05 09:30 UTCGHSA enrichment
  4. 2026-09-04 20:39 UTCEG score recompute
  5. 2026-09-04 20:38 UTCGHSA enrichment
  6. 2026-09-04 07:19 UTCEG score recompute
  7. 2026-09-04 07:18 UTCGHSA enrichment
  8. 2026-09-04 05:07 UTCEPSS rescore
  9. 2026-09-03 18:27 UTCGHSA enrichment
  10. 2026-09-03 05:29 UTCGHSA enrichment
  11. 2026-09-03 01:10 UTCEG score recompute
  12. 2026-09-03 01:10 UTCGHSA enrichment
  13. 2026-09-02 14:12 UTCEPSS rescore
  14. 2026-09-02 12:17 UTCGHSA enrichment
  15. 2026-09-01 23:25 UTCEG score recompute
  16. 2026-09-01 23:25 UTCGHSA enrichment
  17. 2026-09-01 22:22 UTCEG score recompute
  18. 2026-09-01 22:22 UTCGHSA enrichment
  19. 2026-09-01 20:21 UTCEG score recompute
  20. 2026-09-01 20:21 UTCGHSA enrichment
  21. 2026-09-01 13:54 UTCEPSS rescore
  22. 2026-09-01 09:45 UTCEG score recompute
  23. 2026-09-01 09:45 UTCGHSA enrichment
  24. 2026-09-01 04:40 UTCEPSS rescore
  25. 2026-09-01 04:40 UTCEPSS rescore
  26. 2026-08-31 20:54 UTCGHSA enrichment
  27. 2026-08-31 17:16 UTCGHSA enrichment
  28. 2026-08-31 03:27 UTCEG score recompute
  29. 2026-08-31 03:27 UTCGHSA enrichment
  30. 2026-08-30 19:18 UTCEPSS rescore
  31. 2026-08-30 19:17 UTCEPSS rescore
  32. 2026-08-30 14:36 UTCGHSA enrichment
  33. 2026-08-30 01:42 UTCEG score recompute
  34. 2026-08-30 01:42 UTCGHSA enrichment
  35. 2026-08-30 01:22 UTCEPSS rescore
  36. 2026-08-29 12:51 UTCGHSA enrichment
  37. 2026-08-28 23:58 UTCEG score recompute
  38. 2026-08-28 23:58 UTCGHSA enrichment
  39. 2026-08-28 21:42 UTCEPSS rescore
  40. 2026-08-28 08:35 UTCGHSA enrichment
  41. 2026-08-27 19:31 UTCEG score recompute
  42. 2026-08-27 19:31 UTCGHSA enrichment
  43. 2026-08-27 14:25 UTCEPSS rescore
  44. 2026-08-27 06:40 UTCEG score recompute
  45. 2026-08-27 06:40 UTCGHSA enrichment
  46. 2026-08-26 17:21 UTCEG score recompute
  47. 2026-08-26 16:22 UTCEG score recompute
  48. 2026-08-26 15:53 UTCEG score recompute
  49. 2026-08-26 10:33 UTCEG score recompute
  50. 2026-08-26 10:32 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-80205?
CVE-2026-80205 is a high vulnerability published on August 26, 2026. NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic…
When was CVE-2026-80205 disclosed?
CVE-2026-80205 was first published in the National Vulnerability Database on August 26, 2026, with the most recent update on September 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-80205 actively exploited?
CVE-2026-80205 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 58.9% of all scored CVEs.
What is the CVSS score of CVE-2026-80205?
CVE-2026-80205 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-80205?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-80205, 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-2026-80205

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