Vulnerability · Published Oct 8, 2026 · Assigned by Go
CVE-2026-94439HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
High 7.5
In plain English
A high-severity security flaw in net/http from Go standard library. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | delve | 1.26.1-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:10 | go-toolset | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | go-toolset | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | go-toolset | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-bin | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-bin | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-bin | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-docs | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-docs | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-docs | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-misc | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-misc | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-misc | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-race | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-race | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-race | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-src | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-src | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-src | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-tests | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-tests | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-tests | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| Alpine:v3.24 | go | 1.26.9-r0 | ALPINE-CVE-2026-94439 |
| Debian:12 | golang-1.19 | no fix listed | DEBIAN-CVE-2026-94439 |
| Debian:13 | golang-1.24 | no fix listed | DEBIAN-CVE-2026-94439 |
| Debian:14 | golang-1.26 | 1.26.9-1 | DEBIAN-CVE-2026-94439 |
| Debian:14 | golang-1.27 | 1.27.2-1 | DEBIAN-CVE-2026-94439 |
| Go | stdlib | 1.26.9, 1.27.2 | GO-2026-6613 |
| Ubuntu:22.04:LTS | golang-1.17 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.18 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.20 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.21 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.21 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.22 | 1.22.2-2~22.04.4 | USN-8935-1 |
| Ubuntu:22.04:LTS | golang-1.22 | 1.22.2-2~22.04.4 | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.22 | 1.22.2-2ubuntu0.5 | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.22 | 1.22.2-2ubuntu0.5 | USN-8935-1 |
| Ubuntu:22.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:22.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:24.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.10 | golang-1.26 | no fix listed | UBUNTU-CVE-2026-94439 |
| Ubuntu:26.10 | golang-1.27 | no fix listed | UBUNTU-CVE-2026-94439 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Go standard library | net/http | 0 – before 1.26.91.27.0-0 – before 1.27.2 |
Weakness: CWE-444 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N