Stanza: RCE via pickle deserialization in the lemmatizer

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

• stanza 1.15.0Fixed version · GitHub Advisories · pip package stanza: upgrade to 1.15.0 or later (affected = 1.14.0)

[ Packages ]Affected open-source packages

• stanza pipAffected = 1.14.0 · fixed in 1.15.0 · GHSA-gh9r-c94j-cmp5

[ References ]References

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