Description

sigstore-java is a sigstore java client for interacting with sigstore infrastructure. sigstore-java has insufficient verification for a situation where a bundle provides a invalid signature for a checkpoint. This bug impacts clients using any variation of KeylessVerifier.verify(). Currently checkpoints are only used to ensure the root hash of an inclusion proof was provided by the log in question. Failing to validate that means a bundle may provide an inclusion proof that doesn't actually correspond to the log in question. This may eventually lead a monitor/witness being unable to detect when a compromised logs are providing different views of themselves to different clients. There are other mechanisms right now that mitigate this, such as the signed entry timestamp. Sigstore-java currently requires a valid signed entry timestamp. By correctly verifying the signed entry timestamp we can make certain assertions about the log signing the log entry (like the log was aware of the artifact signing event and signed it). Therefore the impact on clients that are not monitors/witnesses is very low. This vulnerability is fixed in 1.2.0.

Classification

CVE ID: CVE-2024-54140

CVSS Base Severity: LOW

CVSS Base Score: 2.1

Affected Products

Vendor: sigstore

Product: sigstore-java

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 17.81% (scored less or equal to compared to others)

EPSS Date: 2025-02-03 (when was this score calculated)

References

https://github.com/sigstore/sigstore-java/security/advisories/GHSA-jp26-88mw-89qr
https://github.com/sigstore/sigstore-conformance/pull/139
https://github.com/sigstore/sigstore-java/commit/23fb4885e6704a5df4977f7acf253a745349edf9

Timeline