High severity · published Jul 15, 2026
CVE-2026-45793
Composer: Github Actions issued GITHUB_TOKEN disclosure in GitHub Actions logs
7.5
CVSS
1%
EPSS
No
On KEV
Description
Composer is a dependency Manager for the PHP language. Prior to 1.10.28, 2.2.28, and 2.9.8, Composer\IO\BaseIO::loadConfiguration() validates GitHub OAuth tokens with the regex ^[.A-Za-z0-9_]+$ and interpolates rejected tokens into an UnexpectedValueException; GitHub Actions GITHUB_TOKEN values using the ghs_<id>_<base64url-JWT> format can contain -, fail validation, and be disclosed to stderr or CI logs. This issue is fixed in versions 1.10.28, 2.2.28, and 2.9.8.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 63% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
composer · composer
>= 1.0, < 1.10.28; >= 2.0.0, < 2.2.28; >= 2.3.0, < 2.9.8 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45793
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45793
github.com
https://github.com/composer/composer/commit/3f5e7f9fbfa541137d6d1d5643ec3b718e9d5039
github.com
https://github.com/composer/composer/commit/65e6390c49f1a11cd8b660d81822086db51fe2d1
github.com
https://github.com/composer/composer/commit/e66c8fdb7ff5409bd2f358c5f194038e49e93714
github.com
https://github.com/composer/composer/pull/12853
github.com
https://github.com/composer/composer/pull/12855
github.com
https://github.com/composer/composer/releases/tag/1.10.28
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