CVE-2026-78681

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Source
https://cve.org/CVERecord?id=CVE-2026-78681
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-78681.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-78681
Aliases
  • GHSA-97qj-x29f-37w7
Downstream
Published
2026-08-25T01:30:37.749Z
Modified
2026-08-28T11:30:54.416352357Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
NLTK before 3.10.3 Entity Expansion DoS via ElementTree
Details

NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.

Database specific 
{
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
        "CWE-776"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/78xxx/CVE-2026-78681.json"
}
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 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "3.10.3"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "DESCRIPTION"
    ]
}

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-2026-78681.json"