Information Disclosure in undici (CVE-2026-13697)
Summary
Vulnerability in undici (CVE-2026-13697). Confidential information can be exposed externally. Exploitable via private. Mitigation: upgrade to 8.9.0 or later.
Original description
The description as published by the source.
undici's cache interceptor mishandles malformed Cache-Control private directives. In undici 7.0.0 up to before 7.29.0 and 8.0.0 up to before 8.9.0, a response carrying a degenerate qualified private directive, such as private set to an empty value, can be stored in the default shared cache and later served to a different caller with the same cache key, disclosing private response bodies and headers including Set-Cookie. Separately, a Cache-Control header that combines an unqualified private directive with a qualified one triggers an uncaught TypeError in the cache-control parser, which rejects the request and, depending on the consumer's error handling, can terminate the process. Both issues affect applications using the cache interceptor in shared mode, including the default configuration. The issues are fixed in undici 7.29.0 and 8.9.0.
Source: NIST National Vulnerability Database 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-2026-13697 has been found in undici.
Attackers can target a specific entry point like private over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.4/10.
What to do: upgrade undici to 8.9.0 or later.
If unsure, ask your IT team or search "undici CVE-2026-13697" on the vendor's site.
CVE-2026-13697 (undici) — CWE-200 / CVSS v3 7.4
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: private / TypeError / Vary / concat
Patched: 8.9.0 — apply immediately
Workaround: Until patched, avoid shared interceptors.cache() for user-specific responses, use type: 'private', or disable caching for affected origins.
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.
Information disclosure (CWE-200) exists in undici. Attackers reach the vulnerable code path via private without authentication.
Check the vendor advisory for the affected versions of undici. Attack surface: private / TypeError / Vary / concat.
Severity: High (CVSS 7.4/10). Confidential information can be exposed externally.
Update to 8.9.0.
Workaround: Until patched, avoid shared interceptors.cache() for user-specific responses, use type: 'private', or disable caching for affected origins.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'undici' . 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
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1Identify exposure identify
grep -r 'undici' . | 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
undiciを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Until patched, avoid shared `interceptors.cache()` for user-specific responses, use `type: 'private'`, or disable caching for affected origins.パッチが適用されるまでの応急処置として、Until patched, avoid shared
interceptors.cache()for user-specific responses, usetype: 'private', or disable caching for affected origins. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade undici to 8.9.0ステージング環境で 8.9.0 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。
-
4Post-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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-13697 node-undici
- Ubuntu UBUNTU-CVE-2026-13697 node-undici
References
- advisory cna.openjsf.org
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- web github.com
- web github.com
- web github.com
- web github.com