Low severity · published Jul 31, 2026
CVE-2026-54787
sigstore-go fails to check signature timestamps against a signing key's validity period
3.1
CVSS
0.1%
EPSS
No
On KEV
Description
sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.1, sigstore-go does not check a bundle signing timestamp against the validity window of an ExpiringKey wrapping a self-managed long-lived signing key without a certificate, which can allow an attacker holding expired key material to sign accepted bundles. This issue is fixed in version 1.2.1.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
sigstore-go · sigstore
< 1.2.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-54787
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-54787
github.com
https://github.com/sigstore/sigstore-go/commit/4594ab4c779d08be1f4419803a8249188f35ed5f
github.com
https://github.com/sigstore/sigstore-go/pull/642
github.com
https://github.com/sigstore/sigstore-go/releases/tag/v1.2.1
github.com
https://github.com/sigstore/sigstore-go/security/advisories/GHSA-wqqc-jjcq-vfxm
More from sigstore-go
7.5
CVE-2026-49834
sigstore-go: Multi-log threshold bypass via single compromised log
7.5
CVE-2024-45395
Unbounded loop over untrusted input can lead to endless data attack