CVE-2026-15176nginx Heap Buffer Overflow
Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive.
Published Oct 14, 2026 · Updated Oct 18, 2026 · Also known as EUVD-2026-101112, GHSA-cvv4-j4mx-w8q5
Key Facts
Patch in the next maintenance window- CVE-2026-15176 is a critical-severity vulnerability (CVSS 9.2 v4) affecting Azl3 Httpd 2.4.68-1 (Microsoft), nginx (debian), nginx-main (redhat) and 2 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 0.5% probability of exploitation in the next 30 days.
- Fixed versions are available, including nginx 1.30.4-8, NGINX Open Source 1.30.6, NGINX Open Source 1.31.7.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Scores
CVSS v4
9.2
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
EPSS (30-day exploit likelihood)
0.5%
Higher than 42.7% of all scored CVEs
Exploit maturity
None known
ATLAS score
27/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
None known
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryRHSA-2026:83427
- advisoryRelease Notes
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.
Affected Products
10 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Azl3 Httpd 2.4.68-1Microsoft | See advisory | n/a |
| nginxdebian | See advisory | 1.30.4-8 |
| nginx-mainredhat | See advisory | 1.30.6-1.hum1 |
| NGINX Open Source | >= 0.1.29, >= 1.31.0 | 1.30.6 |
| NGINX Plus | >= R34, >= 37.1.0 | * |
Patched Releases
nginx
1.30.4-8
NGINX Open Source
1.30.6, 1.31.7
NGINX Plus
*, 37.0.5.1, 37.1.0.1
nginx-main
1.30.6-1.hum1
Timeline
Publicly disclosed
Oct 14, 2026
Last updated
Oct 18, 2026
Weakness Type
- CWE-122 Heap-based Buffer Overflow
- CWE-787 Out-of-bounds Write
References
- advisoryRHSA-2026:83427
- advisoryRelease Notes
- othermy.f5.com · K000162416
FAQ
Common Questions.
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.
Affected: Azl3 Httpd 2.4.68-1 (Microsoft); nginx (debian); nginx-main (redhat), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including nginx 1.30.4-8, NGINX Open Source 1.30.6, NGINX Open Source 1.31.7.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
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