CVE catalog
CVE-2026-56866
Go vulnerabilities
- Severity
- Critical · CVSS 9.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.47% · Oct 25, 2026
When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive response, Transport returns the connection to the idle pool. Because CONNECT requests do not have a request body, the server may interpret the trailing body bytes as a subsequent pipelined HTTP/1.1 request on the connection, leaving the pooled connection desynchronized and causing the next caller that reuses it to read the response to the injected request. In reverse proxies (including httputil.ReverseProxy) that forward CONNECT requests through a shared Transport, this can lead to cross-user response poisoning.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | golang-1.19 | bookworm | 1.19.8-2 | vulnerable |
| Bitnami | golang | Not reported | 1.26.9 | fixed |
| Bitnami | golang | Not reported | 1.27.2 | fixed |
| Go | stdlib | Not reported | 1.26.9 | fixed |
| Go | stdlib | Not reported | 1.27.2 | fixed |
| Ubuntu | golang-1.22 | noble | 1.22.2-2ubuntu0.5 | fixed |
| Ubuntu | golang-1.22-doc | noble | 1.22.2-2ubuntu0.5 | fixed |
| Ubuntu | golang-1.22-go | noble | 1.22.2-2ubuntu0.5 | fixed |
| Ubuntu | golang-1.22-src | noble | 1.22.2-2ubuntu0.5 | fixed |
| Ubuntu | golang-1.10 | 14.04 | 1.10.4-2ubuntu1~14.04.1 | vulnerable |
| Ubuntu | golang-1.10 | 16.04 | 1.10.4-2ubuntu1~16.04.1 | vulnerable |
| Ubuntu | golang-1.10 | 16.04 | 1.10.4-2ubuntu1~16.04.2 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6-0ubuntu1 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6-0ubuntu2 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6-0ubuntu3 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6-0ubuntu4 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6-0ubuntu5 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6.1-0ubuntu1 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6.2-0ubuntu5~16.04 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6.2-0ubuntu5~16.04.2 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6.2-0ubuntu5~16.04.3 | vulnerable |
| Ubuntu | golang-1.6 | 16.04 | 1.6.2-0ubuntu5~16.04.4 | vulnerable |
| Ubuntu | golang-1.13 | pro | 1.13.8-1ubuntu2 | vulnerable |
| Ubuntu | golang-1.13 | pro | 1.13.8-1ubuntu2.22.04.1 | vulnerable |
| Ubuntu | golang-1.13 | pro | 1.13.8-1ubuntu2.22.04.1+esm1 | vulnerable |
| Ubuntu | golang-1.13 | pro | 1.13.8-1ubuntu2.22.04.2 | vulnerable |
| Ubuntu | golang-1.18 | pro | 1.18.1-1ubuntu1~18.04.3 | vulnerable |
| Ubuntu | golang-1.18 | pro | 1.18.1-1ubuntu1~18.04.4 | vulnerable |
| Ubuntu | golang-1.18 | pro | 1.18.1-1ubuntu1~18.04.4+esm1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10~rc1-1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10~rc1-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10~rc1-2ubuntu1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10~rc2-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10.1-1ubuntu2 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10.4-2ubuntu1~18.04.1 | vulnerable |
| Ubuntu | golang-1.10 | 18.04 | 1.10.4-2ubuntu1~18.04.2 | vulnerable |
| Ubuntu | golang-1.16 | pro | 1.16.2-0ubuntu1~20.04 | vulnerable |
| Ubuntu | golang-1.16 | pro | 1.16.2-0ubuntu1~20.04.1 | vulnerable |
| Ubuntu | golang-1.16 | pro | 1.16.2-0ubuntu1~20.04.1+esm1 | vulnerable |
| Ubuntu | golang-1.8 | 18.04 | 1.8.3-2ubuntu1 | vulnerable |
| Ubuntu | golang-1.8 | 18.04 | 1.8.3-2ubuntu1.18.04.1 | vulnerable |
| Ubuntu | golang-1.9 | 18.04 | 1.9.1-2ubuntu1 | vulnerable |
| Ubuntu | golang-1.9 | 18.04 | 1.9.2-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.9 | 18.04 | 1.9.2-3ubuntu1 | vulnerable |
| Ubuntu | golang-1.9 | 18.04 | 1.9.3-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.9 | 18.04 | 1.9.4-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.1-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.3-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.4-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.5-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.6-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.6-2ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.7-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.8-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.8-1ubuntu1.1 | vulnerable |
| Ubuntu | golang-1.13 | 20.04 | 1.13.8-1ubuntu1.2 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14~beta1-1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14~beta1-2 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14~rc1-1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14-1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14.1-1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14.2-1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14.2-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14.3-2ubuntu2~20.04.1 | vulnerable |
| Ubuntu | golang-1.14 | 20.04 | 1.14.3-2ubuntu2~20.04.2 | vulnerable |
| Ubuntu | golang-1.18 | 20.04 | 1.18.1-1ubuntu1~20.04.1 | vulnerable |
| Ubuntu | golang-1.18 | 20.04 | 1.18.1-1ubuntu1~20.04.2 | vulnerable |
| Ubuntu | golang-1.18 | 20.04 | 1.18.1-1ubuntu1~20.04.3 | vulnerable |
| Ubuntu | golang-1.20 | 20.04 | 1.20.3-1ubuntu0.1~20.04 | vulnerable |
| Ubuntu | golang-1.20 | 20.04 | 1.20.3-1ubuntu0.1~20.04.1 | vulnerable |
| Ubuntu | golang-1.21 | 20.04 | 1.21.1-1~ubuntu20.04.1 | vulnerable |
| Ubuntu | golang-1.21 | 20.04 | 1.21.1-1~ubuntu20.04.2 | vulnerable |
| Ubuntu | golang-1.21 | 20.04 | 1.21.1-1~ubuntu20.04.3 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17-1ubuntu2 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17.3-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17.3-1ubuntu2 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17.13-3ubuntu1 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17.13-3ubuntu1.2 | vulnerable |
| Ubuntu | golang-1.17 | 22.04 | 1.17.13-3ubuntu1.3 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18~beta1-0ubuntu1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18~beta2-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18~beta2-1ubuntu2 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18~rc1-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18.1-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18.1-1ubuntu1.1 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18.1-1ubuntu1.2 | vulnerable |
| Ubuntu | golang-1.18 | 22.04 | 1.18.1-1ubuntu1.3 | vulnerable |
| Ubuntu | golang-1.20 | 22.04 | 1.20.3-1ubuntu0.1~22.04 | vulnerable |
| Ubuntu | golang-1.20 | 22.04 | 1.20.3-1ubuntu0.1~22.04.1 | vulnerable |
| Ubuntu | golang-1.21 | 22.04 | 1.21.1-1~ubuntu22.04.1 | vulnerable |
| Ubuntu | golang-1.21 | 22.04 | 1.21.1-1~ubuntu22.04.2 | vulnerable |
| Ubuntu | golang-1.21 | 22.04 | 1.21.1-1~ubuntu22.04.3 | vulnerable |
| Ubuntu | golang-1.21 | 22.04 | 1.21.1-1~ubuntu22.04.4 | vulnerable |
| Ubuntu | golang-1.22 | 22.04 | 1.22.2-2~22.04 | vulnerable |
| Ubuntu | golang-1.22 | 22.04 | 1.22.2-2~22.04.1 | vulnerable |
| Ubuntu | golang-1.22 | 22.04 | 1.22.2-2~22.04.2 | vulnerable |
| Ubuntu | golang-1.22 | 22.04 | 1.22.2-2~22.04.3 | vulnerable |
| Ubuntu | golang-1.22 | 22.04 | 1.22.2-2~22.04.4 | fixed |
| Ubuntu | golang-1.23 | 22.04 | 1.23.1-1~22.04 | vulnerable |
| Ubuntu | golang-1.23 | 22.04 | 1.23.1-1~22.04.2 | vulnerable |
| Ubuntu | golang-1.23 | 22.04 | 1.23.1-1~22.04.3 | vulnerable |
| Ubuntu | golang-1.24 | 22.04 | 1.24.4-1ubuntu1~22.04.1 | vulnerable |
| Ubuntu | golang-1.24 | 22.04 | 1.24.4-1ubuntu1~22.04.2 | vulnerable |
| Ubuntu | golang-1.24 | 22.04 | 1.24.13-2~22.04.1 | vulnerable |
| Ubuntu | golang-1.24 | 22.04 | 1.24.13-2~22.04.2 | vulnerable |
| Ubuntu | golang-1.25 | 22.04 | 1.25.14-1~ubuntu0.22.04.1 | vulnerable |
| Ubuntu | golang-1.26 | 22.04 | 1.26.8-1~ubuntu0.22.04.2 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.1-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.3-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.4-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.5-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.6-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.7-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.7-2 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.8-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.8-1build1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.9-1 | vulnerable |
| Ubuntu | golang-1.21 | 24.04 | 1.21.9-1ubuntu0.1 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22~rc1-2 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.0-1 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.0-2 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.1-1 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.1-1build1 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2ubuntu0.1 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2ubuntu0.2 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2ubuntu0.3 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2ubuntu0.4 | vulnerable |
| Ubuntu | golang-1.22 | 24.04 | 1.22.2-2ubuntu0.5 | fixed |
| Ubuntu | golang-1.23 | 24.04 | 1.23.1-1~24.04 | vulnerable |
| Ubuntu | golang-1.23 | 24.04 | 1.23.1-1~24.04.1 | vulnerable |
| Ubuntu | golang-1.24 | 24.04 | 1.24.4-1ubuntu1~24.04.1 | vulnerable |
| Ubuntu | golang-1.24 | 24.04 | 1.24.4-1ubuntu1~24.04.2 | vulnerable |
| Ubuntu | golang-1.24 | 24.04 | 1.24.13-2~24.04.1 | vulnerable |
| Ubuntu | golang-1.25 | 24.04 | 1.25.14-1~ubuntu0.24.04.1 | vulnerable |
| Ubuntu | golang-1.26 | 24.04 | 1.26.8-1~ubuntu0.24.04.2 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.0-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.2-3 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.4-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.5-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.6-2 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.7-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.8-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.10 | 1.26.8-2 | vulnerable |
| Ubuntu | golang-1.27 | 26.10 | 1.27~rc1-1 | vulnerable |
| Ubuntu | golang-1.27 | 26.10 | 1.27~rc2-1 | vulnerable |
| Ubuntu | golang-1.27 | 26.10 | 1.27~rc3-1 | vulnerable |
| Ubuntu | golang-1.27 | 26.10 | 1.27.0-1 | vulnerable |
| Ubuntu | golang-1.27 | 26.10 | 1.27.1-1 | vulnerable |
| Ubuntu | golang-1.23 | 26.04 | 1.23.10-1 | vulnerable |
| Ubuntu | golang-1.24 | 26.04 | 1.24.4-1ubuntu1 | vulnerable |
| Ubuntu | golang-1.24 | 26.04 | 1.24.9-1 | vulnerable |
| Ubuntu | golang-1.24 | 26.04 | 1.24.13-2 | vulnerable |
| Ubuntu | golang-1.25 | 26.04 | 1.25.0-0ubuntu1 | vulnerable |
| Ubuntu | golang-1.25 | 26.04 | 1.25.7-2 | vulnerable |
| Ubuntu | golang-1.25 | 26.04 | 1.25.14-1~ubuntu0.26.04.1 | vulnerable |
| Ubuntu | golang-1.26 | 26.04 | 1.26~rc3-2 | vulnerable |
| Ubuntu | golang-1.26 | 26.04 | 1.26.0-1 | vulnerable |
| Ubuntu | golang-1.26 | 26.04 | 1.26.8-1~ubuntu0.26.04.2 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | golang-1.19 | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Bitnami | golang | Bitnami | Not reported | 1.26.9 | Not reported | BIT-GOLANG-2026-56866 | Not reported |
| Bitnami | golang | Bitnami | Not reported | 1.27.2 | Not reported | BIT-GOLANG-2026-56866 | Not reported |
| Go | stdlib | Go | Not reported | 1.26.9 | Not reported | GO-2026-6605 | Not reported |
| Go | stdlib | Go | Not reported | 1.27.2 | Not reported | GO-2026-6605 | Not reported |
| Ubuntu | golang-1.22 | deb | noble | 1.22.2-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | golang-1.22-doc | deb | noble | 1.22.2-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | golang-1.22-go | deb | noble | 1.22.2-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | golang-1.22-src | deb | noble | 1.22.2-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | golang-1.22 | deb | 22.04 | 1.22.2-2~22.04.4 | Not reported | UBUNTU-CVE-2026-56866 | Not reported |
| Ubuntu | golang-1.22 | deb | 24.04 | 1.22.2-2ubuntu0.5 | Not reported | UBUNTU-CVE-2026-56866 | Not reported |
Notes
[bookworm] golang-1.19: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [golang-1.19]Affected
Details (2)
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
- [golang-1.19-doc]Affected
Source package: [golang-1.19]
Details (2)
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
- [golang-1.19-go]Affected
Source package: [golang-1.19]
Details (2)
1.19.8-2· amd64 · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
1.19.8-2· arm64 · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
- [golang-1.19-src]Affected
Source package: [golang-1.19]
Details (2)
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
1.19.8-2· all · bookwormAffected
usn · golang-1.19 · debian · bookworm; usn · golang-1.19 · debian · 12
[Debian 13 (Trixie)]
- [golang-1.24]Affected
Details (2)
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
- [golang-1.24-doc]Affected
Source package: [golang-1.24]
Details (2)
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
- [golang-1.24-go]Affected
Source package: [golang-1.24]
Details (2)
1.24.4-1· amd64 · trixieAffected
usn · golang-1.24 · debian · 13
1.24.4-1· arm64 · trixieAffected
usn · golang-1.24 · debian · 13
- [golang-1.24-src]Affected
Source package: [golang-1.24]
Details (2)
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
1.24.4-1· all · trixieAffected
usn · golang-1.24 · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_12093-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-56866]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-56866]
- [https://osv.dev/vulnerability/GO-2026-6605]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-56866]
- [https://security-tracker.debian.org/tracker/CVE-2026-56866]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56866.json]
- [https://ubuntu.com/security/notices/USN-8935-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3841.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]