Summary
sigstore-go has a multi-log threshold bypass via single compromised log
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
There is no workaround, beyond relying on trusted logs.
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.
CVE-2026-49834 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.2.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Has the problem been patched? What versions should users upgrade to?
Upgrade to v1.1.5.
Frequently Asked Questions
- What is CVE-2026-49834? CVE-2026-49834 is a medium-severity security vulnerability in github.com/sigstore/sigstore-go (go), affecting versions <= 1.1.4. It is fixed in 1.2.0.
- How severe is CVE-2026-49834? CVE-2026-49834 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/sigstore/sigstore-go are affected by CVE-2026-49834? github.com/sigstore/sigstore-go (go) versions <= 1.1.4 is affected.
- Is there a fix for CVE-2026-49834? Yes. CVE-2026-49834 is fixed in 1.2.0. Upgrade to this version or later.
- Is CVE-2026-49834 exploitable, and should I be worried? Whether CVE-2026-49834 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-49834 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-49834? Upgrade
github.com/sigstore/sigstore-goto 1.2.0 or later.