CVE-2026-42945
Publication date 14 May 2026
Last updated 21 May 2026
Ubuntu priority
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, 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.
Why is this CVE high priority?
Possible remote code execution issue
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| nginx | 26.04 LTS resolute |
Fixed 1.28.3-2ubuntu1.1
|
| 25.10 questing |
Fixed 1.28.0-6ubuntu1.3
|
|
| 24.04 LTS noble |
Fixed 1.24.0-2ubuntu7.8
|
|
| 22.04 LTS jammy |
Fixed 1.18.0-6ubuntu14.11
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
8.1 · High
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
References
Related Ubuntu Security Notices (USN)
- USN-8271-1
- nginx vulnerability
- 14 May 2026