# CVE-2026-42945

## Summary

- **CVE ID:** CVE-2026-42945
- **Severity:** CRITICAL
- **CVSS Score:** 9.2 (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)
- **CWE:** CWE-122
- **Published:** May 13, 2026
- **Last Modified:** Sep 9, 2026

## 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.

## Affected Products

- F5 — NGINX Plus (R37)
- F5 — NGINX Plus (R36)
- F5 — NGINX Plus (R32)
- F5 — NGINX Open Source (1.31.0)
- F5 — NGINX Open Source (0.6.27)

## References

- [CNA](https://my.f5.com/manage/s/article/K000161019)
- [CVE](https://depthfirst.com/nginx-rift)
- [CVE](https://github.com/DepthFirstDisclosures/Nginx-Rift)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-42945)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2477116)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42945.json)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17790)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18063)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19159)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18041)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17791)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17751)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17792)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17793)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17752)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17794)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17753)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18029)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19371)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19374)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19372)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17417)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22396)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22393)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22394)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22390)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22388)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22389)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22382)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22383)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:20442)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:20444)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:21275)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:58981)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 68.05%
- **EPSS Percentile:** 99.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._