CVE catalog

CVE-2026-56853

When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being a

[CVE catalog]

Severity: High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Aug 13, 2026, 9:58:53 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.57% · Oct 25, 2026

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
Go	stdlib	Not reported	`1.27.0-rc.3`	fixed
Go	stdlib	Not reported	`1.25.13`	fixed
Go	stdlib	Not reported	`1.26.6`	fixed

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
Go	stdlib	Go	Not reported	`1.27.0-rc.3`	Not reported	Not reported	Not reported
Go	stdlib	Go	Not reported	`1.25.13`	Not reported	Not reported	Not reported
Go	stdlib	Go	Not reported	`1.26.6`	Not reported	Not reported	Not reported

Notes

[bookworm] golang-1.19: Limited support

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[golang-1.19]Affected
Details (2)
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
[golang-1.19-doc]Affected
Source package: [golang-1.19]
Details (2)
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
[golang-1.19-go]Affected
Source package: [golang-1.19]
Details (2)
- 1.19.8-2 · amd64 · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
- 1.19.8-2 · arm64 · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
[golang-1.19-src]Affected
Source package: [golang-1.19]
Details (2)
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12
- 1.19.8-2 · all · bookworm
  Affected
  nvd · golang-1.19 · debian · bookworm; nvd · golang-1.19 · debian · 12

[Debian 13 (Trixie)]

[golang-1.24]Affected
Details (2)
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13
[golang-1.24-doc]Affected
Source package: [golang-1.24]
Details (2)
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13
[golang-1.24-go]Affected
Source package: [golang-1.24]
Details (2)
- 1.24.4-1 · amd64 · trixie
  Affected
  nvd · golang-1.24 · debian · 13
- 1.24.4-1 · arm64 · trixie
  Affected
  nvd · golang-1.24 · debian · 13
[golang-1.24-src]Affected
Source package: [golang-1.24]
Details (2)
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13
- 1.24.4-1 · all · trixie
  Affected
  nvd · golang-1.24 · debian · 13

Observed: Oct 23, 2026, 9:41:59 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [Go Vulnerability Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]