CVE-2026-28684

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

State: Published
Severity: 6.6 Medium
Published: Apr 20, 2026
Updated: Apr 20, 2026
Reserved: Mar 2, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	6.6 Medium	CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H	GitHub_M

Weaknesses

CWE-59 Improper Link Resolution Before File Access ('Link Following')
CWE-61 UNIX Symbolic Link (Symlink) Following

Affected Products

Product	Versions
python-dotenvtheskumar	< 1.2.2Affected

References

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