Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| sigstore | timestamp-authority | < 2.0.6 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | golang-github-sigstore-timestamp-authority | 2.1.0-1 | — |
| Debian 13 | golang-github-sigstore-timestamp-authority | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | golang-github-sigstore-timestamp-authority | No fix yet | — |
| Ubuntu 26.04 LTS | golang-github-sigstore-timestamp-authority | No fix yet | — |
| Ubuntu 25.10 | golang-github-sigstore-timestamp-authority | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES 15 SP6 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES 15 SP5 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES 15 SP4 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | docker | 29.4.0_ce-160000.7.1 | SUSE-SU-2026:22367-1 |
| SLES for SAP 15 SP6 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES for SAP 15 SP5 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES for SAP 15 SP4 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLES 16.0 | docker | 29.4.0_ce-160000.7.1 | SUSE-SU-2026:22367-1 |
| SLE Micro 6.2 | docker | 29.4.0_ce-160000.7.1 | SUSE-SU-2026:24410-1, SUSE-SU-2026:22285-1 |
| SLE Micro 6.1 | docker | 29.4.0_ce-slfo.1.1_10.1 | SUSE-SU-2026:24279-1, SUSE-SU-2026:22456-1 |
| SLE Micro 6.0 | docker | 29.4.0_ce-11.1 | SUSE-SU-2026:24318-1, SUSE-SU-2026:22513-1 |
| SLE Micro 5.5 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLE Micro 5.4 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLE Micro 5.3 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLE HPC 15 SP5 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
| SLE HPC 15 SP4 | docker | 29.4.0_ce-150000.253.1 | SUSE-SU-2026:2692-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | docker | 29.4.0_ce-40.1 | openSUSE-SU-2026:11144-1 |
| openSUSE Tumbleweed | hauler | 1.4.3-1.1 | openSUSE-SU-2026:10702-1 |
| openSUSE Tumbleweed | trivy | 0.70.0-1.1 | openSUSE-SU-2026:10651-1 |
| openSUSE Leap 16.0 | docker | 29.4.0_ce-160000.7.1 | openSUSE-SU-2026:22158-1, openSUSE-SU-2026:21060-1 |
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | nerdctl | 2.2.2-1.amzn2023.0.1 | ALAS2023-2026-1605 |
| Amazon Linux 2 | nerdctl | 2.2.2-1.amzn2.0.1 | ALAS2-2026-3265 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | aactl | 0.4.12-r50 | — |
| Wolfi rolling | buildkitd | 0.29.0-r6 | — |
| Wolfi rolling | cosign | 3.0.5-r9 | — |
| Wolfi rolling | crossplane-2.2 +1 | 2.2.0-r8 | — |
| Wolfi rolling | docker-cli-buildx | 0.33.0-r5 | — |
| Wolfi rolling | dockerd-29 | 29.4.1-r0 | — |
| Wolfi rolling | falcoctl | 0.12.2-r10 | — |
| Wolfi rolling | flux-source-controller | 1.8.2-r4 | — |
| Wolfi rolling | gh | 2.90.0-r0 | — |
| Wolfi rolling | gitsign | 0.14.0-r17 | — |
| Wolfi rolling | goreleaser | 2.15.3-r1 | — |
| Wolfi rolling | ko | 0.18.1-r12 | — |
| Wolfi rolling | kubescape | 4.0.5-r0 | — |
| Wolfi rolling | kyverno-1.17 +5 | 1.17.1-r15 | — |
| Wolfi rolling | kyverno-notation-aws | 1.1-r50 | — |
| Wolfi rolling | neuvector-sigstore-interface | 0_git20260405-r1 | — |
| Wolfi rolling | policy-controller +1 | 0.15.1-r4 | — |
| Wolfi rolling | ratify | 1.4.0-r36 | — |
| Wolfi rolling | ratify-licensechecker-compat | 1.4.5-r4 | — |
| Wolfi rolling | sigstore-scaffolding-tuf-server +1 | 0.7.31-r12 | — |
| Wolfi rolling | skaffold | 2.18.3-r2 | — |
| Wolfi rolling | slsa-verifier | 2.7.1-r23 | — |
| Wolfi rolling | spire-agent | 1.14.5-r2 | — |
| Wolfi rolling | tekton-chains | 0.26.2-r8 | — |
| Wolfi rolling | teleport-18.6 +2 | 18.6.8-r29 | — |
| Wolfi rolling | tflint | 0.61.0-r10 | — |
| Wolfi rolling | tkn | 0.44.1-r3 | — |
| Wolfi rolling | trivy | 0.69.3-r12 | — |
| Wolfi rolling | trivy-operator | 0.30.1-r6 | — |
| Wolfi rolling | vexctl | 0.4.1-r19 | — |
| Wolfi rolling | witness | 0.10.2-r20 | — |
| Wolfi rolling | zarf | 0.74.2-r6 | — |
| Wolfi rolling | zot | 2.1.16-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/sigstore/timestamp-authority | all versions | — | GO-2026-5763 |
| Go | github.com/sigstore/timestamp-authority/v2 | < 2.0.6 | 2.0.6 | GHSA-xm5m-wgh2-rrg3 |
Advisories 17
- WID-SEC-2026-3046 IBM Concert: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
- SUSE-SU-2026:24410-1 Security update for docker SUSE / openSUSE Security Updates · Oct 30, 2026
- SUSE-SU-2026:24318-1 Security update for docker SUSE / openSUSE Security Updates · Oct 27, 2026
- SUSE-SU-2026:24279-1 Security update for docker SUSE / openSUSE Security Updates · Oct 27, 2026
- openSUSE-SU-2026:22158-1 Security update for docker SUSE / openSUSE Security Updates · Oct 24, 2026
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:22513-1 Security update for docker SUSE / openSUSE Security Updates · Jul 9, 2026
- SUSE-SU-2026:22456-1 Security update for docker SUSE / openSUSE Security Updates · Jul 4, 2026
- SUSE-SU-2026:22367-1 Security update for docker SUSE / openSUSE Security Updates · Jul 2, 2026
- SUSE-SU-2026:2692-1 Security update for docker SUSE / openSUSE Security Updates · Jul 1, 2026
- openSUSE-SU-2026:21060-1 Security update for docker SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:22285-1 Security update for docker SUSE / openSUSE Security Updates · Jun 30, 2026
- openSUSE-SU-2026:11144-1 docker-29.4.0_ce-40.1 on GA media SUSE / openSUSE Security Updates · Jun 30, 2026
- openSUSE-SU-2026:10702-1 hauler-1.4.3-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2026
- ALAS2023-2026-1605 Important: nerdctl security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- ALAS2-2026-3265 Important: nerdctl security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 29, 2026
- openSUSE-SU-2026:10651-1 trivy-0.70.0-1.1 on GA media SUSE / openSUSE Security Updates · Apr 29, 2026