CVE-2026-48815: Sigstore Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-52v5-jr5w-gjxr
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CVSS 7.5
CWE-347
Published
Advisory Summary

CVE-2026-48815 is a HIGH (CVSS 7.5) remote code execution vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Sigstore libraries in the npm ecosystem. The issue involves sigstore's `certificateoids` verification constraints are silently dropped and never enforced. Remediation is available by upgrading affected packages to version 4.1.1.

CVE-2026-48815 at a Glance

CVE Identifier CVE-2026-48815
GHSA Identifier GHSA-52v5-jr5w-gjxr
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Sigstore
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-48815

To remediate this vulnerability, upgrade all affected Sigstore dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

sigstore fixed: 4.1.1 
npm install sigstore@4.1.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls sigstore

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-48815, inspect your project dependencies using npm:

npm ls sigstore

Analyze the terminal output to locate any version of Sigstore in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.1.1), your application is affected.

Note: The npm ls sigstore command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Sigstore, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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 ```javascript const { createVerificationPolicy } = require("sigstore/dist/config"); const policy = createVerificationPolicy({ certificateIssuer: "https://issuer.example", certificateIdentityEmail: "victim@example.com", certificateOIDs: { "1.2.3.4": "required-value", }, }); console.log("certificateOIDs" in policy, JSON.stringify(policy)); // false {"subjectAlternativeName":"victim@example.com","extensions":{"issuer":"https://issuer.example"}} ``` ### 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 Affected Sigstore Versions

1 component(s)
Fixed Versions:
4.1.1
Product / Package Ecosystem Affected Versions Fixed Version
sigstore
npm/sigstore
npm
< 4.1.1
4.1.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/sigstore/sigstore-js/security/advisories/GHSA-52v5-jr5w-gjxr
Sigstore Source Repository REPOSITORY
https://github.com/sigstore/sigstore-js

Frequently Asked Questions

What is CVE-2026-48815?
CVE-2026-48815 is a security vulnerability in Sigstore involving sigstore's `certificateOIDs` verification constraints are silently dropped and never enforced under CWE-347: Improper Verification of Cryptographic Signature.
Which Sigstore versions are affected?
Affected versions include releases prior to 4.1.1 across affected packages: sigstore.
What version fixes CVE-2026-48815?
Upgrading to 4.1.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is sigstore affected?
Yes, sigstore is affected in releases prior to 4.1.1. Upgrade your dependency to 4.1.1 or later.
What is the CVSS score of CVE-2026-48815?
CVE-2026-48815 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2026-48815?
CVE-2026-48815 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check npm dependencies for CVE-2026-48815?
Run the dependency tree command: 'npm ls sigstore'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-52v5-jr5w-gjxr",
  "modified" : "2026-07-01T19:58:28Z",
  "published" : "2026-07-01T19:58:28Z",
  "aliases" : [ "CVE-2026-48815" ],
  "summary" : "sigstore's `certificateOIDs` verification constraints are silently dropped and never enforced",
  "details" : "### Summary\n\nThe documented `certificateOIDs` option in `sigstore.verify()` is accepted by the public API but discarded before verification, so required certificate extension OIDs are never checked.\n\n### Details\n\nThe 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`.\n\nAs 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.\n\nThis is reachable from supported usage through the documented `certificateOIDs` verify option.\n\n### PoC\n\n```javascript\nconst { createVerificationPolicy } = require(\"sigstore/dist/config\");\n\nconst policy = createVerificationPolicy({\n  certificateIssuer: \"https://issuer.example\",\n  certificateIdentityEmail: \"victim@example.com\",\n  certificateOIDs: {\n    \"1.2.3.4\": \"required-value\",\n  },\n});\n\nconsole.log(\"certificateOIDs\" in policy, JSON.stringify(policy));\n// false {\"subjectAlternativeName\":\"victim@example.com\",\"extensions\":{\"issuer\":\"https://issuer.example\"}}\n```\n\n### Impact\n\nApplications 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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "sigstore"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.1.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.1.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/sigstore/sigstore-js/security/advisories/GHSA-52v5-jr5w-gjxr"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sigstore/sigstore-js"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-01T19:58:28Z",
    "nvd_published_at" : null
  }
}