CVE-2026-115878

HIGH 7.8

Stanza: RCE via pickle deserialization in the lemmatizer

CVSS Score

7.8

EPSS Score

0.0%

EPSS Percentile

0th

Stanza 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.

CWE	CWE-94 CWE-502
Vendor	stanfordnlp
Product	stanza
Published	Nov 3, 2026

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CVSS v3 Breakdown

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

stanfordnlp / stanza

= 1.14.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/stanfordnlp/stanza/security/advisories/GHSA-gh9r-c94j-cmp5 github.com: https://github.com/stanfordnlp/stanza/pull/1649 github.com: https://github.com/stanfordnlp/stanza/commit/b21e1c9b47b4fccff21d3b0a6c0687a19410c2f0 github.com: https://github.com/stanfordnlp/stanza/releases/tag/v1.15.0