CVE-2026-48142

NGINX ngx_http_charset_module vulnerability

Assigner: f5
Reserved: 02.06.2026 Published: 17.06.2026 Updated: 17.06.2026

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When content is served or proxied through a location block with both source_charset utf-8; and a charset directive (for example, charset koi8-r;) configured, remote, unauthenticated attackers can send requests (in conjunction with conditions beyond their 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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
CVSS Score: 4.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	Low

CVSS 3.1

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS Score: 6.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	High	Integrity	None	Integrity	None
Attack Requirements	None	Availability	Low	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	F5
Product	NGINX Open Source
Versions	Default: unknown affected from 1.13.10 to 1.31.2 (excl.) affected from 1.30.0 to 1.30.3 (excl.)

Vendor

Product

NGINX Open Source

Versions

Default: unknown

affected from 1.13.10 to 1.31.2 (excl.)
affected from 1.30.0 to 1.30.3 (excl.)

Vendor	F5
Product	NGINX Plus
Versions	Default: unaffected affected from 37.0 to 37.0.2.1 (excl.) affected from R36 to R36 P6 (excl.)

Vendor

Product

NGINX Plus

Versions

Default: unaffected

affected from 37.0 to 37.0.2.1 (excl.)
affected from R36 to R36 P6 (excl.)

Credits

"F5 acknowledges p4p3r of CYBERONE and Han Yan of Xiaomi for bringing this issue to our attention and following the highest standards of coordinated disclosure." reporter

References

Problem Types