CVE-2026-85008 is a low-severity (CVSS 3.7) CWE-345 vulnerability in undici. A fix is available for undici — see the affected versions and patch details below.
undici vulnerable to caching and replay of unsafe HTTP method responses
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-85008.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-85008 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
undicinpmDescription
Impact
undici's interceptors.cache() documents that it caches only safe HTTP methods. However, its internal skip-list is built by subtracting the configured methods from the safe-methods set, so an unsafe method (POST, PUT, PATCH, DELETE) never lands in the skip-list and is looked up against the cache store. Combined with the storage gate (canCacheResponse) having no method check, a heuristically-cacheable response (for example a 404) with an explicit Cache-Control: max-age=... to an unsafe method is stored and replayed on a subsequent identical request. The application's state-changing request never reaches the origin, and undici serves a fabricated response from the cache instead. This occurs with the default configuration (methods: ['GET']), which the public API does not allow widening to unsafe methods, so no application misuse is required; an untrusted origin can trigger it purely through its own response headers.
Patches
Upgrade to 7.29.1 or 8.10.2. The cache interceptor no longer reads from or writes to the cache for unsafe HTTP methods, while still invalidating existing cache entries on successful unsafe requests.
Workarounds
None.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | undici | ≥ 7.0.0&&< 7.29.1 | 7.29.1npm install undici@7.29.1 |
| 📦npm | undici | ≥ 8.0.0&&< 8.10.2 | 8.10.2npm install undici@8.10.2 |
Affected Products
undicinodejsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update undici to 7.29.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-85008 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Low impact vulnerability in undici's cache interceptor can lead to integrity issues by caching responses for unsafe HTTP methods. Under certain default configurations, a malicious remote origin could cause stale or manipulated responses to be served from the cache, bypassing intended state changes. This risk is…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2026-85008 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Hardened Images | nodejs26-main-11.19.0-1.26.7.0.1.5.2.hum1 | RHSA-2026:54389 |
| Red Hat Hardened Images | nodejs24-main-11.16.0-1.24.18.1.0.2.2.hum1 | RHSA-2026:54438 |
| Red Hat Hardened Images | grafana12-4-main-12.4.10-0.2.hum1 | RHSA-2026:66008 |
Frequently Asked Questions
Is CVE-2026-85008 in your dependencies?
Find it across npm, including transitive dependencies.