CVE-2026-49834: sigstore-go has a multi-log threshold bypass via single compromised log
Affects github.com/sigstore/sigstore-goSource GCVE Database
Not known to be exploited · CVSS 5.9 Medium : upgrade to 1.2.0 when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.2.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade github.com/sigstore/sigstore-go to 1.2.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Gogithub.com/sigstore/sigstore-go | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
### Impact _What kind of vulnerability is it? Who is impacted?_ A verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) expected defense-in-depth against the compromise of a single log instance. However, threshold counting counted verified witnesses per-entry or per-validation-path rather than per-log-authority. As a result, a single compromised transparency log could forge multiple entries with different indices, and a single compromised CT log could verify multiple times (either across multiple certificate chains or via multiple embedded SCTs), fully satisfying the multi-log threshold requirements and defeating the multi-log policy. Note that this does not affect Cosign, as Cosign sets a threshold of 1. ### Patches _Has the problem been patched? What versions should users upgrade to?_ Upgrade to v1.1.5. ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ There is no workaround, beyond relying on trusted logs.
References
- github.com/sigstore/sigstore-go/security/advisories/GHSA-9vcr-p3rj-q5q6 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-49834 (opens in a new tab)
- github.com/sigstore/sigstore-go/pull/633 (opens in a new tab)
- github.com/sigstore/sigstore-go/commit/dbb07e62623edd5b175fb9dd5a41dcb85a159207 (opens in a new tab)
- github.com/sigstore/sigstore-go (opens in a new tab)
- github.com/sigstore/sigstore-go/releases/tag/v1.2.0 (opens in a new tab)