CVE-2026-85008
Received Received - Intake

Cache Poisoning in Undici HTTP Client

Vulnerability report for CVE-2026-85008, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: openjs

Description

undici's cache interceptor documents that only safe HTTP methods are cached, but its logic to skip caching is built by subtracting the configured methods from the set of safe methods, so an unsafe method such as POST, PUT, or DELETE is never placed in the skip list and instead falls through to the full cache-read path. The response-storage gate also lacked a method check, so a response to an unsafe request that is heuristically cacheable or carries an explicit Cache-Control directive is stored and later replayed from cache. Because response headers from a remote origin are untrusted, an origin can answer once with a cacheable status and then have the client's own subsequent state-changing requests to that path served from the stale cache entry without ever reaching the origin, an integrity failure that occurs under the interceptor's default configuration. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-05
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
undici undici From 7.0.0 (inc) to 7.29.1 (inc)
undici undici From 8.0.0 (inc) to 8.10.2 (inc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-345 The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability involves undici's cache interceptor incorrectly handling HTTP methods. It claims only safe methods are cached but fails to exclude unsafe methods like POST, PUT, or DELETE from caching logic. Responses to unsafe requests that are cacheable are stored and later replayed, allowing stale cached responses to be served without reaching the origin server. This affects versions from 7.0.0 to 7.29.1 and 8.0.0 to 8.10.2.

Impact Analysis

An attacker could exploit this to serve stale or incorrect cached responses to users, bypassing the origin server. This could lead to users receiving outdated or manipulated data without the server's knowledge, potentially causing confusion or incorrect actions based on stale information.

Mitigation Strategies

Upgrade undici to version 7.29.1 or 8.10.2 or later to address the cache integrity failure in the interceptor.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-85008. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart