GHSA-xgjw-pm74-86q4 sigstore-js has Insufficient Verification of Data Authenticity

• npm @sigstore/verify: >= 3.1.0, < 3.1.1 → fixed in 3.1.1

sigstore-js derives a transparency-log timestamp from `tlogEntries[].integratedTime` and uses it to validate certificate validity windows and satisfy `timestampThreshold`. For bundle v0.2, a tlog entry can be inclusionProof-only (no signed inclusionPromise/set), and the inclusion proof path does not cryptographically bind `integratedTime`. As a result, an attacker who can supply an untrusted bundle can influence time-based verification decisions by choosing `integratedTime`. impact If a consumer accepts attacker-provided bundle v0.2 inputs and relies on tlog-derived timestamps for certificate validity checks, verification can be influenced by an unauthenticated timestamp value. This is a trust gap: `integratedTime` is treated as a trusted observer timestamp under inclusionProof-only mode even though only the signed inclusionPromise/set path binds it. affected code • `packages/verify/src/bundle/index.ts` (adds a transparency-log timestamp whenever `integratedTime != 0`) • `packages/verify/src/timestamp/index.ts` (converts `integratedTime` to a `Date`) • `packages/verify/src/verifier.ts` (verifies timestamps before verifying tlog inclusion) • `packages/verify/src/tlog/index.ts` + `packages/verify/src/tlog/set.ts` (only the inclusionPromise/set path binds `integratedTime`) proof of concept The attached `poc.zip` contains a self-contained harness that reproduces the behavior on the pinned commit and includes both a canonical test and a negative control. repro: 1) extract `poc.zip` into a fresh directory and run the make targets: ```bash unzip poc.zip -d poc cd poc/poc-F-SIG-JS-TLOGTIME-001 make canonical make control ``` 2) confirm `canonical.log` includes: ``` [CALLSITE_HIT]: [PROOF_MARKER]: ``` 3) confirm `control.log` includes: ``` [NC_MARKER]: ``` suggested fix Only treat `integratedTime` as a trusted timestamp when it is cryptographically bound (for example, via a verified signed inclusionPromise/set). For inclusionProof-only entries, do not count `integratedTime` toward `timestampThreshold`, and do not use it for certificate validity decisions unless there is another signed time source (for example, an rfc3161 timestamp). poc.zip PR_DESCRIPTION.md SUBMISSION.md