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VulnerabilityPublished

CVE-2026-1839: huggingface/transformers · Deserialization of Untrusted Data

Affects huggingface/transformersSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium · fixed in 5.0.0 : update huggingface/transformers when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.0 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.0.0
CVSS:3.0/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
huggingfacehuggingface/transformersAffected
  • ≥ unspecified, < v5.0.0rc3
Fixed in–

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AI-suggested

The vulnerability is resolved in huggingface/transformers version v5.0.0rc3. Users should upgrade to this version or later to mitigate the issue. If upgrading is not immediately possible, avoid loading untrusted checkpoint files with affected versions and PyTorch versions below 2.6. Patch status is not explicitly stated beyond the fix in v5.0.0rc3; check the vendor advisory for the latest remediation guidance.

Description

A vulnerability in the HuggingFace Transformers library, specifically in the `Trainer` class, allows for arbitrary code execution. The `_load_rng_state()` method in `src/transformers/trainer.py` at line 3059 calls `torch.load()` without the `weights_only=True` parameter. This issue affects all versions of the library supporting `torch>=2.2` when used with PyTorch versions below 2.6, as the `safe_globals()` context manager provides no protection in these versions. An attacker can exploit this vulnerability by supplying a malicious checkpoint file, such as `rng_state.pth`, which can execute arbitrary code when loaded. The issue is resolved in version v5.0.0rc3.

References

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