OAuth token disclosure via exception interpolation
Published Jul 15, 2026 · Updated Jul 15, 2026
Information disclosure in Composer 1.0 before 1.10.28, 2.0.0 before 2.2.28, and 2.3.0 before 2.9.8 lets attackers read tokens in CI logs. BaseIO::loadConfiguration() rejects tokens containing hyphens under an incomplete allowed-character regex, then embeds the rejected secret verbatim in an exception rendered to stderr. Reaching the disclosure requires a configured GitHub OAuth token in the modern hyphenated format and captured stderr; exposure is bounded by access to the resulting logs and the token's scope and lifetime.
Summary
What happened
Information disclosure in Composer 1.0 before 1.10.28, 2.0.0 before 2.2.28, and 2.3.0 before 2.9.8 lets attackers read tokens in CI logs. BaseIO::loadConfiguration() rejects tokens containing hyphens under an incomplete allowed-character regex, then embeds the rejected secret verbatim in an exception rendered to stderr. Reaching the disclosure requires a configured GitHub OAuth token in the modern hyphenated format and captured stderr; exposure is bounded by access to the resulting logs and the token's scope and lifetime.
The record
- CVE
- CVE-2026-45793
- Published
- Jul 15, 2026
- Updated
- Jul 15, 2026
- Vendor
- Composer
- Product
- Composer
- Classifications
- CWE-200, T1552.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 15, 2026CVE publishedPublication date reported by the CVE source.
- Jul 15, 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.
- Affected versionversion=>= 1.0, < 1.10.28
- Affected versionversion=>= 2.0.0, < 2.2.28
- Affected versionversion=>= 2.3.0, < 2.9.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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