CVE Explorer
CVE-2026-3635
Summary
When trustProxy is configured with a restrictive trust function (e.g., a specific IP like trustProxy: '10.0.0.1', a subnet, a hop count, or a custom function), the request.protocol and request.host getters read X-Forwarded-Proto and X-Forwarded-Host headers from any connection — including connections from untrusted IPs. This allows an attacker connecting directly to Fastify (bypassing the proxy) to spoof both the protocol and host seen by the application.
Affected Versions
fastify <= 5.
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unaffected","packageURL":"pkg:npm/fastify","product":"fastify","vendor":"fastify","versions":[{"lessThanOrEqual":"5.8.2","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"5.8.3","versionType":"semver"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"HIGH","attackVector":"ADJACENT_NETWORK","availabilityImpact":"NONE","baseScore":6.1,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-348","description":"CWE-348 Use of less trusted source","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"url":"https://cna.openjsf.org/security-advisories.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/references/2
{"url":"https://github.com/fastify/fastify/security/advisories/GHSA-444r-cwp2-x5xf"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/references/0
{"url":"https://www.cve.org/CVERecord?id=CVE-2026-3635"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:0763a7a27d51fd6c790b9a00bf3b067236375fe531bd9490bb19549ff4adf996 · sha256:3ebc558ef058a204… · /containers/cna/references/1
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.