CVE-2026-28684Public exploit

Local file overwrite via cross-device symlink following

Published Apr 20, 2026 · Updated Apr 20, 2026

Symlink following in python-dotenv before 1.2.2 allows local users to overwrite files writable by a calling process. The rewrite context manager passes a symbolic-link path to shutil.move; after a cross-device rename failure, copy2 follows the link and writes replacement content to its target. Exploitation requires directory write access, different filesystems for the temporary file and target, and a process that invokes set_key or unset_key; the target is then corrupted without a race.

CVSS severity6.6
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in python-dotenv before 1.2.2 allows local users to overwrite files writable by a calling process. The rewrite context manager passes a symbolic-link path to shutil.move; after a cross-device rename failure, copy2 follows the link and writes replacement content to its target. Exploitation requires directory write access, different filesystems for the temporary file and target, and a process that invokes set_key or unset_key; the target is then corrupted without a race.

The record

CVE
CVE-2026-28684
Published
Apr 20, 2026
Updated
Apr 20, 2026
Vendor
Saurabh Kumar
Product
python-dotenv
Classifications
CWE-61, CWE-59, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.2.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Saurabh Kumar · python-dotenvversion=< 1.2.2

Published CVSS scores

6.6GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-61UNIX Symbolic Link (Symlink) Following
CWE-59Improper Link Resolution Before File Access ('Link Following')
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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