// For flags

CVE-2026-42945

NGINX ngx_http_rewrite_module vulnerability

Severity Score

9.2
*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track*
*SSVC
Descriptions

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, for systems with Address Space Layout Randomization (ASLR ) disabled, code execution is possible. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

*Credits: F5 acknowledges Zhenpeng (Leo) Lin of depthfirst for bringing this issue to our attention and following the highest standards of coordinated disclosure.
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
System
Vulnerable | Subsequent
Confidentiality
High
None
Integrity
High
None
Availability
High
None
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
* Common Vulnerability Scoring System
SSVC
  • Decision:Track*
Exploitation
None
Automatable
No
Tech. Impact
Total
* Organization's Worst-case Scenario
Timeline
  • 2026-04-30 CVE Reserved
  • 2026-05-13 CVE Published
  • 2026-05-14 CVE Updated
  • 2026-05-15 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-122: Heap-based Buffer Overflow
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
F5
Search vendor "F5"
 NGINX Open Source
Search vendor "F5" for product "NGINX Open Source"
 >= 0.6.27 < 1.30.1
Search vendor "F5" for product "NGINX Open Source" and version " >= 0.6.27 < 1.30.1"
en
Affected