---
cve: "CVE-2026-42533"
severity: "CRITICAL"
cvss: 9.2
epss: "3.5%"
vendor: "F5"
kev: false
exploited: false
published: "2026-07-15 15:16:33"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-05T17:53:00+02:00"
---

# CVE-2026-42533

> 9.2 CRITICAL

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 5e34a17a8f7787e90f41d1af91258a556f0795b4 (Commit)

## Referenzen

- <https://my.f5.com/manage/s/article/K000162097>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-42533) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_