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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| stanfordnlp | stanza | = 1.14.0 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 1 repository
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federiconbaez/cortex9-stanza-lemma-pickle-to-json-model ★ 0 · Nov 9, 2026
Offline educational model of CVE-2026-115878 (Stanza lemma pickle→JSON)
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | stanza | >= 1.14.0, < 1.15.0 | 1.15.0 | GHSA-gh9r-c94j-cmp5 |