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CVE-2026-48815 high CVSS 7.5

Vulnerability in sigstore (CVE-2026-48815)

Summary

Vulnerability in sigstore (CVE-2026-48815). Data can be tampered with by attackers. Exploitable via certificateOIDs. Mitigation: upgrade to 4.1.1 or later.

Original description

The description as published by the source.

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

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 `certifica…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-48815 has been found in sigstore.
Attackers can target a specific entry point like certificateOIDs over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.5/10.
What to do: upgrade sigstore to 4.1.1 or later.
If unsure, ask your IT team or search "sigstore CVE-2026-48815" on the vendor's site.

CVE-2026-48815 (sigstore) — CWE-347 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: certificateOIDs
Patched: 4.1.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-347) exists in sigstore. Attackers reach the vulnerable code path via certificateOIDs without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of sigstore. Attack surface: certificateOIDs.

🔥 Severity

Severity: High (CVSS 7.5/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 4.1.1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'sigstore' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'sigstore' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で sigstore を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade sigstore to 4.1.1

    ステージング環境で 4.1.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

npm sigstore
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.1.1"}]}]

References

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