Heap-based Buffer Overflow Affecting nginx-filesystem package, versions <1:1.24.0-7.module+el9.8.0+40319+5de55ea3.5.rocky.0.1


Severity

Recommended
medium

Based on Rocky Linux security rating.

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.89% (58th percentile)

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  • Snyk IDSNYK-ROCKY9-NGINXFILESYSTEM-19691018
  • published12 Sept 2026
  • disclosed15 Jul 2026

Introduced: 15 Jul 2026

CVE-2026-42533  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:9 nginx-filesystem to version 1:1.24.0-7.module+el9.8.0+40319+5de55ea3.5.rocky.0.1 or higher.
This issue was patched in RLSA-2026:67308.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nginx-filesystem package and not the nginx-filesystem package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:9 relevant fixed versions and status.

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 Base Scores

version 3.1