Description
Impact: @fastify/reply-from versions from 8.3.1 up to but not including 12.6.4 build the internal URL cache key by concatenating the destination and source path without a delimiter. Different destination and source pairs can therefore produce the same key while resolving to different upstream URLs. When getUpstream selects an upstream from request data, a URL cached for one upstream can be reused for a request intended for another upstream, causing cross-upstream data access and modification. The default configuration is affected. Setting disableCache to true prevents the behavior. Patches: upgrade to @fastify/reply-from 12.6.4. Workarounds: pass disableCache: true when registering the plugin.
Affected products
fastify: fastify\/reply-from
References2
- cna.openjsf.org/security-advisories.html Vendor Advisory
- github.com/fastify/fastify-reply-from/security/advisories/GHSA-… Vendor Advisory
Metrics
- CVSS 3.1
-
10.0
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 33 · as of 14 November 2026
- CWE
- CWE-441
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