CVE-2026-39395

unknown

Published 2026-04-08 · Modified 2026-04-09

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CVSS v3

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CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS v4 NEW

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not yet in upstream

VIR risk

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Description

Cosign provides code signing and transparency for containers and binaries. Prior to 3.0.6 and 2.6.3, 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. This vulnerability is fixed in 3.0.6 and 2.6.3.

Predictions

Exploit likelihood

30%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
debian	forky	fixed	`2.6.3-1`
debian	sid	fixed	`2.6.3-1`
debian	trixie	affected
sles		affected

Package impact

Ecosystem	Package	Vulnerable	Fixed
Go	github.com/sigstore/cosign	`>=3.0.0,<3.0.6`	`3.0.6`
Go	github.com/sigstore/cosign	`<2.6.3`	`2.6.3`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.