Vulnerability · Published Jun 17, 2026 · Assigned by f5
CVE-2026-48142NGINX ngx_http_charset_module vulnerability
Medium 4.8
In plain English
A medium-severity out-of-bounds read in NGINX Open Source from F5. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.21 | nginx | 1.26.3-r2 | ALPINE-CVE-2026-48142 |
| Alpine:v3.22 | nginx | 1.28.3-r4 | ALPINE-CVE-2026-48142 |
| Alpine:v3.23 | nginx | 1.28.3-r4 | ALPINE-CVE-2026-48142 |
| Alpine:v3.24 | nginx | 1.30.3-r0 | ALPINE-CVE-2026-48142 |
| Debian:12 | nginx | 1.22.1-9+deb12u9 | DEBIAN-CVE-2026-48142 |
| Debian:13 | nginx | 1.26.3-3+deb13u7 | DEBIAN-CVE-2026-48142 |
| Debian:14 | nginx | 1.30.1-5 | DEBIAN-CVE-2026-48142 |
| Ubuntu:22.04:LTS | nginx | 1.18.0-6ubuntu14.16 | UBUNTU-CVE-2026-48142 |
| Ubuntu:24.04:LTS | nginx | 1.24.0-2ubuntu7.13 | UBUNTU-CVE-2026-48142 |
| Ubuntu:25.10 | nginx | 1.28.0-6ubuntu1.8 | UBUNTU-CVE-2026-48142 |
| Ubuntu:26.04:LTS | nginx | 1.28.3-2ubuntu1.6 | UBUNTU-CVE-2026-48142 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| F5 | NGINX Open Source | 1.13.10 – before 1.31.21.30.0 – before 1.30.3 |
| F5 | NGINX Plus | 37.0 – before 37.0.2.1R36 – before R36 P6 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
References
- https://my.f5.com/manage/s/article/K000161585 vendor-advisory