Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

CVE-2026-54499Stanza: Remote Code Execution via Unsafe Pickle Deserialization in Model Loaders

High 7.5

In plain English

A high-severity unsafe deserialization in stanza from stanfordnlp. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 55.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Stanza is a Stanford NLP Python library for tokenization, sentence segmentation, NER, and parsing of many human languages. Prior to 1.12.2, Stanza model loaders such as stanza.models.common.pretrain.Pretrain.load() attempt torch.load(..., weights_only=True) but fall back to torch.load(..., weights_only=False) on attacker-controllable pickle.UnpicklingError, allowing a malicious .pt pretrain or model file to execute arbitrary pickle code when a Stanza NLP pipeline loads it. This issue is fixed in version 1.12.2.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	stanza	1.12.2	GHSA-v5jw-96jm-7h2c
PyPI	stanza	1.12.2	PYSEC-2026-3075

Affected products (as reported)

Vendor	Product	Versions
stanfordnlp	stanza	< 1.12.2

Weakness: CWE-502, CWE-676 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

References

https://github.com/stanfordnlp/stanza/security/advisories/GHSA-v5jw-96jm-7h2c x_refsource_CONFIRM
https://github.com/stanfordnlp/stanza/pull/1587 x_refsource_MISC
https://github.com/stanfordnlp/stanza/commit/b745008c68c9e50ccb5acd537cb6f2453f8b7ad4 x_refsource_MISC
https://github.com/stanfordnlp/stanza/releases/tag/v1.12.2 x_refsource_MISC