sigstore timestamp-authority

• CVE-2026-49835 Medium 5.9 Sigstore Timestamp Authority: OOM due to unbounded metric label cardinality 0.7%
• CVE-2026-39984 Medium 5.5 Sigstore Timestamp Authority has Improper Certificate Validation in verifier <0.1%
• CVE-2025-66564 High 7.5 Sigstore Timestamp Authority allocates excessive memory during request parsing 0.5%