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Advisory details: github_osv / GHSA-jx89-3qg8-p2mr
Advisory ID github_osv/GHSA-jx89-3qg8-p2mr
Aliases
Summary Duplicate Advisory: Entity-expansion DoS (billion laughs) via remaining raw ElementTree parses (CWE-776) ## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-97qj-x29f-37w7. This link is maintained to preserve external references. ## Original Description 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.
Status Published
Exploitability 0.5
Weighted Severity 7.8
Risk 3.9
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (1)
CWE-776 Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
System Score Found at
cvssv3.1 7.5 https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-jx89-3qg8-p2mr/GHSA-jx89-3qg8-p2mr.json
cvssv4 8.7 https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-jx89-3qg8-p2mr/GHSA-jx89-3qg8-p2mr.json
generic_textual HIGH
Reference id Reference type URL
https://github.com/nltk/nltk/security/advisories/GHSA-97qj-x29f-37w7
https://www.vulncheck.com/advisories/nltk-before-entity-expansion-dos-via-elementtree
CVE-2026-78681 https://nvd.nist.gov/vuln/detail/CVE-2026-78681
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-jx89-3qg8-p2mr/GHSA-jx89-3qg8-p2mr.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: 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/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 Found at https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-jx89-3qg8-p2mr/GHSA-jx89-3qg8-p2mr.json
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.