CVE-2026-16158

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
8.7
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.7
EG Score
8.7(medium)
EPSS
13.8%
KEV
Not listed

Published

July 18, 2026

Last Modified

July 21, 2026

Advisory Details (2)

Auto-updated Jul 18, 2026
Patch available. Sources: github.
github Patch Available

@fastify/reply-from vulnerable to cross-upstream request routing via URL cache key collision · Advisory · fastify/fastify-reply-from · GitHub

https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-v574-6498-x57v
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:53 UTCEG score recompute
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 14:30 UTCEPSS rescore
  6. 2026-07-18 14:05 UTCEG score recompute
  7. 2026-07-18 12:40 UTCEG score recompute
  8. 2026-07-18 12:39 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-16158?
CVE-2026-16158 is a high vulnerability published on July 18, 2026. 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 was CVE-2026-16158 disclosed?
CVE-2026-16158 was first published in the National Vulnerability Database on July 18, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16158 actively exploited?
CVE-2026-16158 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 13.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-16158?
CVE-2026-16158 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-16158?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16158, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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