Out-of-bounds Read in F5 Dos
CVE-2026-48142
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L.
EPSS exploit prediction
EPSS: 0.007 (52.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.003
Affected products
- F5 Dos — versions 4.9.0
- F5 nginx Gateway Fabric
- F5 nginx Ingress Controller
- F5 nginx Instance Manager
- F5 nginx Open Source — versions 1.13.10, 1.30.0
- F5 nginx Open Source
- F5 nginx Plus — versions 37.0, R36
- F5 nginx Plus — versions r36
- F5 Waf
Weakness classification (CWE)
References
- my.f5.com/manage/s/article/K000161585 (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-48142?
- CVE-2026-48142 is a medium-severity vulnerability in F5 Dos, classified under Out-of-bounds Read. CVSS score: 4.8/10. Published 2026-06-17.
- How severe is CVE-2026-48142?
- Medium severity. CVSS v3 base score is 4.8 out of 10.