CVE-2026-42926

Publication date 13 May 2026

Last updated 2 June 2026

Ubuntu priority

Cvss 3 Severity Score

Description

When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
nginx	26.04 LTS resolute	Not affected
	25.10 questing	Not affected
	24.04 LTS noble	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

mdeslaur

introduced in 1.29.4

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
nginx	Upstream: ce3362c Upstream: a0e7429

Severity score breakdown

CVSS version:

Base score 6.3 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Attack requirements	Present
Privileges required	None
User interaction	None
Vulnerable system - Confidentiality impact	None
Vulnerable system - Integrity impact	None
Vulnerable system - Availability impact	None
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	Low
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	6.3 · Medium
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Base score 5.8 · Medium