CVE-2026-48142: F5 NGINX Open Source · Out-of-bounds Read
Affects F5 NGINX Open SourceSource CVE Database V5
Not known to be exploited · CVSS 4.8 Medium : upgrade to 1.31.2 or 1.30.3 when convenient.
Data as of 30 Oct 2026, 20:25 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.31.2, 1.30.3, R36 P6 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:LExploitation evidence
Disclosed: evidence found.
CVE published 17 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade NGINX to 1.31.2 or 1.30.3 (Open Source); R36 P6 or 37.0.2.1 (Plus).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| F5NGINX Open Source | Affected
| Fixed in
|
| F5NGINX Open Source | Affected
| Fixed in
|
| F5NGINX Plus | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, consider avoiding configurations that combine source_charset utf-8 with a charset directive in the ngx_http_charset_module if feasible.
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.