CVE-2026-48815 is a high-severity security vulnerability in sigstore (npm), affecting versions <= 4.1.0. It is fixed in 4.1.1.
Summary The documented certificateOIDs option in sigstore.verify() is accepted by the public API but discarded before verification, so required certificate extension OIDs are never checked. Details The public verify options include certificateOIDs and the documentation says those OID/value pairs “must be present in the certificate’s extension list.” The policy-construction path used by sigstore.verify() and createVerifier() only copies the SAN and issuer settings into the verification policy and completely ignores certificateOIDs. As a result, callers can believe they are constraining verification to certificates carrying specific Fulcio or workload-identifying OIDs, while the actual verifier never receives those constraints. Any bundle that satisfies the remaining checks is accepted even if the required OID extensions are absent or mismatched. This is reachable from supported usage through the documented certificateOIDs verify option. PoC Impact Applications that rely on certificateOIDs to restrict which certificates may sign artifacts receive no such protection. Unauthorized certificates that should be rejected on extension policy can be accepted as long as they satisfy the remaining verification checks.
CVE-2026-48815 has a CVSS score of 7.5 (High). 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 (4.1.1). Upgrading removes the vulnerable code path.
npm
sigstore (<= 4.1.0)sigstore → 4.1.1 (npm)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 instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-48815 is reachable in your applications. Explore open-source security for your team.
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Already deployed Kodem? See CVE-2026-48815 in your environment →Upgrade sigstore to 4.1.1 or later to resolve this vulnerability.
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CVE-2026-48815 is a high-severity security vulnerability in sigstore (npm), affecting versions <= 4.1.0. It is fixed in 4.1.1.
CVE-2026-48815 has a CVSS score of 7.5 (High). 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.
sigstore (npm) versions <= 4.1.0 is affected.
Yes. CVE-2026-48815 is fixed in 4.1.1. Upgrade to this version or later.
Whether CVE-2026-48815 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
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.
Upgrade sigstore to 4.1.1 or later.