9.0Critical
CVE-2026-33805@fastify/reply-from vulnerable to connection header abuse enabling stripping of proxy-added headers
Description
@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from. Upgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later.
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| fastify | fastify/http-proxy | < 11.4.4 | |
| fastify | reply-from | < 12.6.2 | |
| @fastify/reply-from | @fastify/http-proxy | < 11.4.4, fixed 11.4.4 | |
| @fastify/reply-from | @fastify/reply-from | < 12.6.2, fixed 12.6.2 | |
| openshift devspaces | 3.27 | — | |
| Red Hat | Red Hat OpenShift AI (RHOAI) | all versions | |
| Red Hat | Red Hat OpenShift Dev Spaces 3.27 | all versions |
References and patches
- https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37 ExploitMitigationVendor Advisory
- https://cna.openjsf.org/security-advisories.html Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:10175
- https://access.redhat.com/security/cve/CVE-2026-33805
- https://bugzilla.redhat.com/show_bug.cgi?id=2458651
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33805.json
CPE matches (NVD) (2)
cpe:2.3:a:fastify:fastify\/http-proxy:*:*:*:*:*:node.js:*:*< 11.4.4cpe:2.3:a:fastify:reply-from:*:*:*:*:*:node.js:*:*< 12.6.2