| Name | 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| golang-1.19 (PTS) | bookworm | 1.19.8-2 | vulnerable |
| golang-1.24 (PTS) | trixie | 1.24.4-1 | vulnerable |
| golang-1.26 (PTS) | forky, sid | 1.26.10-1 | fixed |
| golang-1.27 (PTS) | forky, sid | 1.27.3-1 | fixed |
| golang-golang-x-net (PTS) | bookworm | 1:0.7.0+dfsg-1 | vulnerable |
| trixie | 1:0.27.0-2 | vulnerable | |
| forky, sid | 1:0.61.0-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| golang-1.19 | source | (unstable) | (unfixed) | |||
| golang-1.24 | source | (unstable) | (unfixed) | |||
| golang-1.25 | source | (unstable) | (unfixed) | |||
| golang-1.26 | source | (unstable) | 1.26.9-1 | |||
| golang-1.27 | source | (unstable) | 1.27.2-1 | |||
| golang-golang-x-net | source | (unstable) | 1:0.60.0-1 |
[trixie] - golang-1.24 <no-dsa> (Minor issue)
[bookworm] - golang-1.19 <postponed> (Minor issue)
[trixie] - golang-golang-x-net <no-dsa> (Minor issue)
[bookworm] - golang-golang-x-net <postponed> (minor issue)
https://www.openwall.com/lists/oss-security/2026/10/08/9
https://github.com/golang/go/issues/81857
Fixed by: https://github.com/golang/go/commit/cbb0fb8b51cba866018b8a0fb4b5458f16c5c80b (go1.27.2)
Fixed by: https://github.com/golang/go/commit/6e049521882c944afc1e519a83971ec421dc2974 (go1.26.9)
Fixed by: https://github.com/golang/net/commit/57f4235f83712a299328015548240512213a3852 (v0.60.0)