CVE-2026-42934: F5 NGINX Plus · Out-of-bounds Read
Affects F5 NGINX PlusSource CVE Database V5
Not known to be exploited · CVSS 4.8 Medium : upgrade to 1.30.1 when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.30.1
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 13 May 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 29 Oct 2026.
What to do
Upgrade NGINX Open Source to 1.30.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| F5NGINX Plus | Affected
| Fixed in– |
| F5NGINX Open Source | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, review configurations involving charset, source_charset, charset_map, and proxy_pass with buffering disabled to assess exposure. Consider avoiding or modifying these configurations if feasible to reduce risk.
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.