NGINX Plus · Vulnerability Exists
Affects nginxSource GCVE Database
Not known to be exploited · CVSS 8.1 High · fixed in 1.18.0-6ubuntu14.21 : patch nginx soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 59% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.18.0-6ubuntu14.21, 1.24.0-2ubuntu7.18, 1.28.3-2ubuntu1.11
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Jul 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 the Ubuntu nginx to 1.18.0-6ubuntu14.21 (package) or 1.24.0-2ubuntu7.18 (package) or 1.28.3-2ubuntu1.11 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu Pro 20.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in– |
Ubuntu Pro 16.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra-legacy/xenialOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
References
- ubuntu.com/security/CVE-2026-42533 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-42533 (opens in a new tab)
- my.f5.com/manage/s/article/K000162097 (opens in a new tab)
- cyberstan.co.uk/nginx-rce/ (opens in a new tab)
- github.com/imbas007/cve-2026-42533 (opens in a new tab)
- ubuntu.com/security/notices/USN-8563-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8563-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8563-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8563-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8563-5 (opens in a new tab)