CVE-2026-16158

10.0 criticalEPSS 0.4%

Critical (10.0) in fastify fastify\/reply-from. EPSS 0.4% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

10.0 critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS: 0.4% chance of exploitation in the next 30 days; higher than 32% of CVEs (scores of 2026-10-31)
CWE: CWE-441
Published: 2026-07-18
Modified: 2026-08-05
Record from: the NVD, synced 2026-10-19

Affected

fastify:fastify\/reply-from

References

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