CVE-2026-42945
NGINX ngx_http_rewrite_module vulnerability
Basic Information
- CVE State
- PUBLISHED
- Reserved Date
- April 30, 2026
- Published Date
- May 13, 2026
- Last Updated
- May 21, 2026
- Vendor
- F5
- Product
- NGINX Plus, NGINX Open Source
- Description
- NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
CVSS Scores
CVSS v4.0
9.2 - CRITICAL
Vector: 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
CVSS v3.1
8.1 - HIGH
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC Information
- Exploitation
- none
- Technical Impact
- total
Exploit Status
- Exploited in the Wild
- Yes (2026-05-19 15:36:39 UTC) Source
Known Exploited Vulnerability Information
| Source | Added Date |
|---|---|
| The Shadowserver (via CIRCL) | 2026-05-19 15:36:39 UTC |
Timeline
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CVE ID Reserved
-
CVE Published to Public
-
Added to KEVIntel