CVE-2024-55655 – sigstore-python has insufficient validation of integration timestamp during verification

https://notcve.org/view.php?id=CVE-2024-55655

sigstore-python is a Python tool for generating and verifying Sigstore signatures. Versions of sigstore-python newer than 2.0.0 but prior to 3.6.0 perform insufficient validation of the "integration time" present in "v2" and "v3" bundles during the verification flow: the "integration time" is verified *if* a source of signed time (such as an inclusion promise) is present, but is otherwise trusted if no source of signed time is present. This does not affect "v1" bundles, as the "v1" bundle format always requires an inclusion promise. Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). • https://github.com/sigstore/sigstore-python/commit/300b502ae99ebfaace124f1f4e422a6a669369cf https://github.com/sigstore/sigstore-python/releases/tag/v3.6.0 https://github.com/sigstore/sigstore-python/security/advisories/GHSA-hhfg-fwrw-87w7 • CWE-20: Improper Input Validation CWE-325: Missing Cryptographic Step •