# CVE-2026-91771

## Summary

- **CVE ID:** CVE-2026-91771
- **Severity:** HIGH
- **CVSS Score:** 8.8 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-22
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 15, 2026

## Description

Weights & Biases wandb before 0.29.0 fails to validate the file name from server responses in the File.download function, allowing path traversal attacks. Attackers controlling the backend can supply file names with directory traversal sequences to write files outside the intended download directory, potentially enabling code execution through modification of shell startup files or Python import paths.

## Affected Products

- wandb — wandb (0)

## References

- [CNA](https://github.com/wandb/wandb/issues/12592)
- [CNA](https://github.com/wandb/wandb/commit/e52558f3a6a94ea816af74969a13a35e5904cad6)
- [CNA](https://github.com/wandb/wandb/releases/tag/v0.29.0)
- [CNA](https://github.com/wandb/wandb/blob/v0.27.2/wandb/apis/public/files.py#L319-L347)
- [CNA](https://github.com/wandb/wandb)
- [CNA](https://www.vulncheck.com/advisories/weights-biases-wandb-before-0.29.0-path-traversal-via-file-download)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.73%
- **EPSS Percentile:** 52.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._