Heap-based buffer overflow in F5 Networks products - CVE-2026-93479

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service or execute arbitrary code.

The vulnerability exists due to a heap-based buffer overflow in the NGINX worker process's map directive with regex matching when processing HTTP requests under configurations where the root directive or access log format references the map's regex capture variables before referencing the map output variable. A remote attacker can send crafted HTTP requests to cause a denial of service or execute arbitrary code.

The same condition can also arise when a non-cacheable variable is used in a string expression under certain conditions. Exploitation depends on conditions beyond the sender's control. Code execution requires Address Space Layout Randomization (ASLR) to be disabled or bypassed. The issue is confined to the data plane, with no control plane exposure.

Affected software

How to mitigate CVE-2026-93479

External References

• https://my.f5.com/manage/s/article/K000162607

Related Security Bulletins

• Multiple vulnerabilities in nginx