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Advisory details: gitlab / pypi/nltk/CVE-2026-78680
Advisory ID gitlab/pypi/nltk/CVE-2026-78680
Aliases CVE-2026-78680
GHSA-6hwm-xvph-95vm
Summary NLTK: Uncontrolled search path when invoking the Graphviz 'dot' binary Two NLTK sites executed the Graphviz `dot` program by bare name, so process creation resolved it via the search path — and on Windows via the current working directory — rather than a validated absolute location. An attacker who can place a file named `dot` where resolution looks (the CWD on Windows, or a writable/relative entry such as `.` on `PATH`) has their binary executed in place of Graphviz (arbitrary code execution). Affected (<= 3.10.2): - `nltk.parse.dependencygraph.dot2img` — called `find_binary("dot")` but discarded the returned validated path and then ran the bare name `["dot", ...]`, so the validation had no effect. - `nltk.translate.api.AlignedSent._repr_svg_` — ran the bare name with no validation at all (IPython SVG rendering). This is the same class already fixed for the senna, weka, boxer, malt, repp and hunpos wrappers. `nltk.internals.find_binary` refuses a CWD-relative match for a bare tool name and returns only a trusted absolute path; the fix runs that path in both sites. ---
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (4)
CWE-427 Uncontrolled Search Path Element
CWE-426 Untrusted Search Path
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-78680.yml
Reference id Reference type URL
https://github.com/advisories/GHSA-6hwm-xvph-95vm
https://github.com/nltk/nltk/commit/1a3cd1764ab3deb084fb66d0ffb4873717659538
https://github.com/nltk/nltk/releases/tag/v3.10.3
https://github.com/nltk/nltk/security/advisories/GHSA-6hwm-xvph-95vm
https://www.vulncheck.com/advisories/nltk-before-arbitrary-code-execution-via-graphviz-dot-binary
CVE-2026-78680 https://nvd.nist.gov/vuln/detail/CVE-2026-78680
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-78680.yml
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

There are no SSVC decisions available.