PYSEC-2026-3751
See a problem?- Import Source
- https://github.com/pypa/advisory-database/blob/main/vulns/nltk/PYSEC-2026-3751.yaml
- JSON Data
- https://api.osv.dev/v1/vulns/PYSEC-2026-3751
- Aliases
-
- CVE-2026-80206
- GHSA-w3v8-gmh9-3wv7
- Published
- 2026-08-26T11:16:40.103Z
- Modified
- 2026-09-02T09:00:05.019508486Z
- Severity
-
- 8.2 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X CVSS Calculator
- Summary
- [none]
- Details
-
NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The tgrepnodeaction function compiles user-supplied regular expressions embedded in /regex/ pattern nodes and executes them via re.search against tree node labels without any validation or timeout. An attacker who controls the tgrep pattern (e.g., via tgreppositions() or tgrep_compile() exposed to external input) can supply a pattern that triggers catastrophic backtracking, causing indefinite CPU saturation that blocks the Python process.
- References
Affected packages
PyPI / nltk
Package
- Name
- nltk
- View open source insights on deps.dev
- Purl
- pkg:pypi/nltk
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0Unknown introduced version / All previous versions are affectedFixed3.10.3
Affected versions
2.*
2.0.1rc2-git
2.0b4
2.0b5
2.0b6
2.0b7
2.0b8
2.0b9
2.0.1rc1
2.0.1rc3
2.0.1rc4
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
0.*
0.8
0.9
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
3.*
3.0.0b1
3.0.0b2
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5b1
3.5
3.6
3.6.1
3.6.2
3.6.3
3.6.4
3.6.5
3.6.6
3.6.7
3.7
3.8
3.8.1
3.9b1
3.9
3.9.1
3.9.2
3.9.3
3.9.4
3.10.0
3.10.1
3.10.2