Signing identity substitution via unchecked OAuth state
Published Jan 26, 2026 · Updated Jan 26, 2026
Cross-site request forgery in Sigstore sigstore-python before 4.2.0 allows man-in-the-middle attackers to substitute a signing identity. _OAuthSession generates a state for the authorization request, but identity_token accepts the callback's code without comparing the returned state to that session value. Exploitation requires interception and user interaction; an attacker-supplied response makes the victim sign under an attacker-controlled identity, without reported data or service impact.
Summary
What happened
Cross-site request forgery in Sigstore sigstore-python before 4.2.0 allows man-in-the-middle attackers to substitute a signing identity. _OAuthSession generates a state for the authorization request, but identity_token accepts the callback's code without comparing the returned state to that session value. Exploitation requires interception and user interaction; an attacker-supplied response makes the victim sign under an attacker-controlled identity, without reported data or service impact.
The record
- CVE
- CVE-2026-24408
- Published
- Jan 26, 2026
- Updated
- Jan 26, 2026
- Vendor
- Sigstore
- Product
- sigstore-python
- Classifications
- CWE-352, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 26, 2026CVE publishedPublication date reported by the CVE source.
- Jan 26, 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?
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- Affected versionversion=< 4.2.0
What conditions does exploitation require?
What is affected?
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.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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