CVE-2026-81724

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Source
https://cve.org/CVERecord?id=CVE-2026-81724
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81724.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-81724
Aliases
  • GHSA-cw6x-m8jw-qmrh
Downstream
Published
2026-08-27T14:51:17.358Z
Modified
2026-08-29T03:30:36.662354890Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion
Details

NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads with nested brackets that exceed Python's recursion limit and raise an unhandled RecursionError, crashing applications that parse user-supplied feature structures or feature grammars.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81724.json",
    "cwe_ids": [
        "CWE-674"
    ],
    "cna_assigner": "VulnCheck"
}
References

Affected packages

Git / github.com/nltk/nltk

Affected ranges

Type
GIT
Repo
https://github.com/nltk/nltk
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
303f6e2ba8e4548a5f54fd65d86bb5c9a949f1db
Database specific
Show details 
{
    "source": [
        "AFFECTED_FIELD",
        "DESCRIPTION"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "3.10.3"
        }
    ]
}

Affected versions

2.*
2.0.1rc1
2.0.1rc2
2.0.1rc3
2.0.1rc4
3.*
3.0.0b1
3.0.2
3.0.3
3.0.4
3.0.5
3.0a4
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
3.4.3
3.4.4
3.5
3.5b1
3.6
3.6.1
3.6.2
3.6.5
3.6.6
3.6.7
3.7
3.8
3.8.1
3.8.2
3.9
3.9.1
3.9.2
3.9.3
3.9.4
v.*
v.3.10.1
v3.*
v3.10.0
v3.10.0-rc1
v3.10.0-rc2
v3.10.1
v3.10.1-rc1
v3.10.1-rc2
v3.10.2
v3.10.2-rc1
v3.9.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81724.json"