Vulnerability details

CVE-2026-15176

F5 NGINX Open SourceF5 NGINX Plus

NGINX ngx_http_core_module vulnerability

CVSS 4.0
9.2Critical

Official description

A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable. Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive. 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 scores

ScoreVersionSourceVector
9.2Critical 4.0 CVEProject cvelistV5 (CNA) (f5) 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
8.1High 3.1 CVEProject cvelistV5 (CNA) (f5) CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

VendorProductVersionsSource
F5 NGINX Open Source 0.1.29 ≤ v < 1.30.6 CVEProject cvelistV5 (CNA)
F5 NGINX Open Source 1.31.0 ≤ v < 1.31.7 CVEProject cvelistV5 (CNA)
F5 NGINX Plus 37.0.0 ≤ v < 37.0.5.1 CVEProject cvelistV5 (CNA)
F5 NGINX Plus 37.1.0 ≤ v < 37.1.0.1 CVEProject cvelistV5 (CNA)
F5 NGINX Plus R33 ≤ v CVEProject cvelistV5 (CNA)
F5 NGINX Plus R34 ≤ v CVEProject cvelistV5 (CNA)
F5 NGINX Plus R35 ≤ v CVEProject cvelistV5 (CNA)
F5 NGINX Plus R36 ≤ v CVEProject cvelistV5 (CNA)

References and advisories

1
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Details

Published
2026-10-14
Last updated
2026-10-15
State
Published
Assigner (CNA)
f5
Kolun priority
40 · Medium

Exploit prediction (EPSS)

0.99%
Probability of exploitation in 30 days
62.9%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
No
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-122
    Heap-based Buffer Overflow