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High 7.4Published Oct 15, 2026

CVE-2026-109829undici vulnerable to cache poisoning and cross-user disclosure via cross-origin redirects

Updated under an hour ago ()

Does this affect you?

It affects undici. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.15%, higher than 4% of scored CVEs.

undici is an HTTP client library for Node.js. In versions 7.0.0 through 7.30.0 and 8.0.0 through 8.12.1, when an originless Agent composes the redirect and cache interceptors in that order with a shared cache store, the cache builds its key from the original request URL before the redirect handler changes the origin, so a response produced after a cross-origin redirect is stored under the original key. An attacker who controls the target of a redirect from a trusted URL can have their response cached under that trusted URL and served to later callers, allowing persistent cache poisoning, and the same key confusion lets a private, non-stored redirect response to a user-specific resource be stored under the original URL and served to a later unauthenticated caller, disclosing private data. Applications are affected only when an originless Agent, a shared cache store, and the redirect-then-cache composition are all used. The issue is fixed in undici 7.30.1 and 8.12.2, which verify the producing origin still matches the cache key and preserve each redirect hop's cache-control policy before storing, and users should upgrade to one of those versions or later. As a workaround, compose the cache interceptor before the redirect interceptor, use per-origin dispatchers and cache stores, or disable shared caching on redirect-capable requests.

CVSS
7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE)
CWE-346, CWE-524
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
0.15% (percentile 4)
Assigned by
openjs
NVD analysis
Undergoing Analysis
Record last updated
Oct 16, 2026
First seen by InfoSec Signals
Oct 15, 2026

Affected products

Affected products
undici undici
undici:undici (from the name)
from 7.0.0 before 7.30.1; 7.30.1 not affected; from 8.0.0 before 8.12.2; 8.12.2 not affected
CNA record

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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