A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format 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.
Metrics
Affected Vendors & Products
References
History
Tue, 20 Oct 2026 00:30:00 +0000
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threat_severity
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threat_severity
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Sun, 18 Oct 2026 16:30:00 +0000
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F5
F5 nginx Open Source F5 nginx Plus |
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| Vendors & Products |
F5
F5 nginx Open Source F5 nginx Plus |
Sat, 17 Oct 2026 00:30:00 +0000
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ssvc
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Wed, 14 Oct 2026 15:00:00 +0000
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| Description | A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format 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. | |
| Title | NGINX map directive and regex matching vulnerability | |
| Weaknesses | CWE-122 | |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: f5
Published: 2026-10-14T14:40:27.107Z
Updated: 2026-10-29T16:59:16.953Z
Reserved: 2026-09-30T21:56:14.601Z
Link: CVE-2026-93479
Updated: 2026-10-15T10:29:30.559Z
Status : Awaiting Analysis
Published: 2026-10-14T15:17:26.810
Modified: 2026-10-15T11:18:08.093
Link: CVE-2026-93479