Stanza: RCE via pickle deserialization in the lemmatizer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-115878
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-03 21:17:02 UTC
Updated2026-11-03 23:17:30 UTC
DescriptionStanza is a Stanford NLP Python library for tokenization, sentence segmentation, NER, and parsing of many human languages. From 1.14.0 until 1.15.0, loading an attacker-supplied lemmatizer checkpoint can execute arbitrary code because stanza/models/lemma/trainer.py stores pos_dict as gzip-compressed pickle bytes and Trainer.load passes the decompressed stream to unrestricted pickle.loads. The outer torch.load call uses weights_only=True, but the nested bytes are treated as a primitive and are not inspected by that allowlist. The path is reachable during pipeline construction through a caller-influenced lemma_model_path, before inference begins. This issue is fixed in version 1.15.0.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS: 0.005970000 probability, percentile 0.487050000 (date 2026-11-04)

Problem Types: CWE-94 | CWE-502 | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection') | CWE-502 CWE-502: Deserialization of Untrusted Data

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Stanfordnlp Stanza affected = 1.14.0 Not specified

References

ReferenceSourceLinkTags
github.com/stanfordnlp/stanza/releases/tag/v1.15.0 [email protected] github.com
github.com/stanfordnlp/stanza/security/advisories/GHSA-gh9r-c94j-cmp5 [email protected] github.com
github.com/stanfordnlp/stanza/pull/1649 [email protected] github.com
github.com/stanfordnlp/stanza/commit/b21e1c9b47b4fccff21d3b0a6c0687a1941... [email protected] github.com
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