CVE-2026-81725

LOWPre-NVD 3.73.7—
EchelonGraph scoreHIGH confidence

Score 3.7 from GitHub Security Advisory published 2026-08-27. a secondary CVSS source baseline 3.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 3.7Exploit: None knownExposed: 0

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

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the read_block method through public APIs like words() and tagged_words() to force repeated rescans and achieve near-quadratic runtime growth.

CVSS v3
3.7
EG Score
3.7(high)
EG Risk
17(Track)
EG Risk 17/100SSVC: 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
Severity37% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

August 27, 2026

Last Modified

September 1, 2026

References (2)

Vendor Advisories for CVE-2026-81725(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
nltk3.10.0-1, 3.10.1-1, 3.9.1-2, 3.9.2-1, 3.9.3-13.10.3-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
nltk0.8 ... 3.9b1 (68 versions)3.10.3—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 35× 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. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-16 19:43 UTCEG score recompute
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-15 03:12 UTCEPSS rescore
  6. 2026-09-15 03:12 UTCEPSS rescore
  7. 2026-09-13 19:56 UTCEG score recompute
  8. 2026-09-11 14:53 UTCEPSS rescore
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-10 20:09 UTCEG score recompute
  11. 2026-09-08 22:01 UTCEPSS rescore
  12. 2026-09-07 20:22 UTCEG score recompute
  13. 2026-09-06 13:48 UTCEPSS rescore
  14. 2026-09-05 15:31 UTCEPSS rescore
  15. 2026-09-04 20:35 UTCEG score recompute
  16. 2026-09-02 14:12 UTCEPSS rescore
  17. 2026-09-01 20:21 UTCEG score recompute
  18. 2026-09-01 20:20 UTCGHSA enrichment
  19. 2026-09-01 13:54 UTCEPSS rescore
  20. 2026-09-01 04:40 UTCEPSS rescore
  21. 2026-09-01 04:40 UTCEPSS rescore
  22. 2026-08-31 20:54 UTCGHSA enrichment
  23. 2026-08-31 20:48 UTCEG score recompute
  24. 2026-08-31 20:48 UTCGHSA enrichment
  25. 2026-08-30 19:18 UTCEPSS rescore
Show 10 more
  1. 2026-08-30 19:17 UTCEPSS rescore
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-28 20:43 UTCEG score recompute
  5. 2026-08-28 20:43 UTCGHSA enrichment
  6. 2026-08-28 19:47 UTCEG score recompute
  7. 2026-08-28 19:47 UTCGHSA enrichment
  8. 2026-08-27 17:24 UTCEG score recompute
  9. 2026-08-27 16:47 UTCEG score recompute
  10. 2026-08-27 16:43 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81725?
CVE-2026-81725 is a low vulnerability published on August 27, 2026. NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the readblock method…
When was CVE-2026-81725 disclosed?
CVE-2026-81725 was first published in the National Vulnerability Database on August 27, 2026, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81725 actively exploited?
CVE-2026-81725 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 86.0% of all scored CVEs.
What is the CVSS score of CVE-2026-81725?
CVE-2026-81725 has a CVSS v3 base score of 3.7 (NVD).
How do I remediate CVE-2026-81725?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81725, 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-2026-81725

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