Staging Environment: Content and features may be unstable or change without notice.
Search for packages
Package details: pkg:deb/debian/cosign@2.6.2-1
purl pkg:deb/debian/cosign@2.6.2-1
Next non-vulnerable version 2.6.3-1
Latest non-vulnerable version 2.6.3-1
Risk 3.1
Vulnerabilities affecting this package (1)
Vulnerability Summary Fixed by
VCID-8k12-ju2w-cygz
Aliases:
CVE-2026-39395
GHSA-w6c6-c85g-mmv6
Cosign's verify-blob-attestation reports false positive when payload parsing fails ## Description `cosign verify-blob-attestation` may erroneously report a "Verified OK" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. ## Impact When `cosign verify-blob-attestation` is used without `--check-claims` set to `true`, an attestation that has a valid signature but a malformed or unparsable payload would be incorrectly validated. Additionally, systems relying on `--type <predicate type>` to reject attestations with mismatched types would be lead to trust the unexpected attestation type. ## Patches v3.0.6, v2.6.3 ## Workarounds Always set `--check-claims=true` for attestation verification.
2.6.3-1
Affected by 0 other vulnerabilities.
Vulnerabilities fixed by this package (2)
Vulnerability Summary Aliases
VCID-8k12-ju2w-cygz Cosign's verify-blob-attestation reports false positive when payload parsing fails ## Description `cosign verify-blob-attestation` may erroneously report a "Verified OK" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. ## Impact When `cosign verify-blob-attestation` is used without `--check-claims` set to `true`, an attestation that has a valid signature but a malformed or unparsable payload would be incorrectly validated. Additionally, systems relying on `--type <predicate type>` to reject attestations with mismatched types would be lead to trust the unexpected attestation type. ## Patches v3.0.6, v2.6.3 ## Workarounds Always set `--check-claims=true` for attestation verification. CVE-2026-39395
GHSA-w6c6-c85g-mmv6
VCID-93qu-3cgz-j7a2 Cosign verification accepts any valid Rekor entry under certain conditions ### Impact A Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This vulnerability only affects users that provide a trusted root via `--trusted-root` or when fetched automatically from a TUF repository, when no trusted key material is provided via `SIGSTORE_REKOR_PUBLIC_KEY`. When using the default flag values in Cosign v3 to sign and verify (`--use-signing-config=true` and `--new-bundle-format=true` for signing, `--new-bundle-format=true` for verification), users are unaffected. Cosign v2 users are affected using the default flag values. This issue had previously been fixed in https://github.com/sigstore/cosign/security/advisories/GHSA-8gw7-4j42-w388 but recent refactoring caused a regression. We have added testing to prevent a future regression. #### Steps to Reproduce ``` echo blob > /tmp/blob cosign sign-blob -y --new-bundle-format=false --bundle /tmp/bundle.1 --use-signing-config=false /tmp/blob cosign sign-blob -y --new-bundle-format=false --bundle /tmp/bundle.2 --use-signing-config=false /tmp/blob jq ".rekorBundle |= $(jq .rekorBundle /tmp/bundle.2)" /tmp/bundle.1 > /tmp/bundle.3 cosign verify-blob --bundle /tmp/bundle.3 --certificate-identity-regexp='.*' --certificate-oidc-issuer-regexp='.*' /tmp/blob ``` ### Patches Upgrade to Cosign v2.6.2 or Cosign v3.0.4. This does not affect Cosign v1. ### Workarounds You can provide trusted key material via a set of flags under certain conditions. The simplest fix is to upgrade to the latest Cosign v2 or v3 release. Note that the example below works for `cosign verify`, `cosign verify-blob, `cosign verify-blob-attestation`, and `cosign verify-attestation`. ``` SIGSTORE_REKOR_PUBLIC_KEY=<path to Rekor pub key> cosign verify-blob --use-signing-config=false --new-bundle-format=false --bundle=<path to bundle> <artifact> ``` CVE-2026-22703
GHSA-whqx-f9j3-ch6m

Date Actor Action Vulnerability Source VulnerableCode Version
2026-04-19T02:54:55.739446+00:00 Debian Importer Fixing VCID-8k12-ju2w-cygz https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T11:16:11.717943+00:00 Debian Importer Fixing VCID-93qu-3cgz-j7a2 https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-16T09:24:45.149985+00:00 Debian Importer Affected by VCID-8k12-ju2w-cygz https://security-tracker.debian.org/tracker/data/json 38.4.0
2026-04-13T08:13:32.560901+00:00 Debian Importer Fixing VCID-93qu-3cgz-j7a2 https://security-tracker.debian.org/tracker/data/json 38.3.0
2026-04-02T17:13:33.199088+00:00 Debian Importer Fixing VCID-93qu-3cgz-j7a2 https://security-tracker.debian.org/tracker/data/json 38.1.0