CVE-2026-42934

NGINX ngx_http_charset_module vulnerability

State: Published
Severity: 6.3 Medium
Published: May 13, 2026
Updated: Jun 8, 2026
Reserved: Apr 30, 2026

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When charset, source_charset, and charset_map and proxy_pass with disabled buffering ("off") directives are configured, unauthenticated attackers can send requests that with conditions beyond the attackers' control to cause a heap buffer over-read in the NGINX worker process, leading to limited disclosure of memory or a restart.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N	f5
3.1	4.8 Medium	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L	f5

Weaknesses

CWE-125 Out-of-bounds Read

Affected Products

Product	Versions
NGINX PlusF5	R37 and laterNot affected R36 to before R36 P4Affected R32 to before R32 P6Affected
NGINX Open SourceF5	1.31.0 and laterNot affected 0.3.50 to before 1.30.1Affected

References

https://my.f5.com/manage/s/article/K000161028vendor-advisorypatch

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