Description
NGINX JavaScript has a vulnerability when the js_fetch_proxy directive is configured with at least one client-controlled NGINX variable (for example, $http_*, $arg_*, $cookie_*) and a location invoking the ngx.fetch() operation from NGINX JavaScript. An unauthenticated attacker 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
References (1)
Core 1
Core References
Vendor Advisory vendor-advisory
https://my.f5.com/manage/s/article/K000161307
Scores
CVSS v3
8.1
EPSS
0.0009
EPSS Percentile
26.1%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-122
Status
published
Products (1)
F5/NGINX JavaScript
0.9.4 - 0.9.9
Published
May 19, 2026
Tracked Since
May 19, 2026