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VulnerabilityPublished Updated

CVE-2026-49834: sigstore-go has a multi-log threshold bypass via single compromised log

Affects github.com/sigstore/sigstore-goSource GCVE Database

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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

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Gogithub.com/sigstore/sigstore-goAffected
  • <1.2.0
Fixed in
  • 1.2.0

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

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