CVE-2026-39984
Sigstore Timestamp Authority has Improper Certificate Validation in verifier
描述
Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Versions 2.0.5 and below contain an authorization bypass vulnerability in the VerifyTimestampResponse function. VerifyTimestampResponse correctly verifies the certificate chain signature, but the TSA-specific constraint checks in VerifyLeafCert uses the first non-CA certificate from the PKCS#7 certificate bag instead of the leaf certificate from the verified chain. An attacker can exploit this by prepending a forged certificate to the certificate bag while the message is signed with an authorized key, causing the library to validate the signature against one certificate but perform authorization checks against another. This vulnerability only affects users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service itself or sigstore-go. The issue has been fixed in version 2.0.6.
如何修補 CVE-2026-39984
要修補 CVE-2026-39984,請將受影響套件升級到下列已修補版本。
- —未列出修補版本
- —升級至 2.0.6 或更新版本
CVE-2026-39984 正在被利用嗎?
低 — EPSS 為 0.0%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- from 0
- from 0, < 2.0.6
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N |