Vulnerability in Sigstore Sigstore-Go
CVE-2026-54787
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.
EPSS: 0.001 (0.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Sigstore Sigstore-go — versions < 1.2.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-54787?
- CVE-2026-54787 is a low-severity vulnerability in Sigstore Sigstore-Go, classified under Use of a Key Past its Expiration Date. CVSS score: 3.1/10. Published 2026-07-31.
- How severe is CVE-2026-54787?
- Low severity. CVSS v3 base score is 3.1 out of 10.