CVE-2026-28684

python-dotenv: Symlink following in set_key allows arbitrary file overwrite via cross-device rename fallback

python-dotenv reads key-value pairs from a .env file and can set them as environment variables. Prior to version 1.2.2, `set_key()` and `unset_key()` in python-dotenv follow symbolic links when rewriting `.env` files, allowing a local attacker to overwrite arbitrary files via a crafted symlink when a cross-device rename fallback is triggered. Users should upgrade to v.1.2.2 or, as a workaround, apply the patch manually.

Affected

theskumar · python-dotenv

CVSS v3.1 GITHUB

6.6 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H

EPSS

0.19% chance of exploitation in the next 30 days, 8th percentile

Published

2026-04-20

Proof-of-concept exploits (1)

• advisories/GHSA-mf9w-mj56-hr94

Security advisories

• theskumar/python-dotenv/security/advisories/GHSA-mf9w-mj56-hr94
• theskumar/python-dotenv/commit/790c5c02991100aa1bf41ee5330aca75edc51311

References

• CVE Record
• NVD entry