Medium severity · published Jan 10, 2026
CVE-2026-22703
Cosign verification accepts any valid Rekor entry under certain conditions
5.5
CVSS
0.1%
EPSS
No
On KEV
Description
Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
cosign · sigstore
< 3.0.4; < 2.6.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-22703
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-22703
Patch
https://github.com/sigstore/cosign/commit/6832fba4928c1ad69400235bbc41212de5006176
Issue Tracking
https://github.com/sigstore/cosign/pull/4623
Exploit
https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m
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