CVE-2026-78659

Description

When "Trailer" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a "Trailer" header that declares a large number of fields, causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits. This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.

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Produits concernés

• Go standard library net/http
• Go standard library net/http/internal/http2
• golang.org/x/net/http2

Scores CVSS

Faiblesses (CWE)

• CWE-405

Références

• https://go.dev/cl/847185
• https://go.dev/cl/847314
• https://go.dev/issue/81857
• https://groups.google.com/g/golang-announce/c/U2fTuyDJznI
• https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs
• https://pkg.go.dev/vuln/GO-2026-6603

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories