Vulnerability 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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| F5 | Dos | >= 4.3.0, <= 4.7.0 |
| F5 | Nginx Gateway Fabric | >= 1.3.0, <= 1.6.2 |
| F5 | Nginx Ingress Controller | >= 3.5.0, <= 3.7.2 |
| F5 | Nginx Instance Manager | >= 2.16.0, <= 2.21.1 |
| F5 | Nginx Open Source | >= 0.6.27, <= 1.30.0 |
| F5 | Nginx Plus | >= r32, <= r36 |
| F5 | Waf | >= 4.9.0, <= 4.16.0 |
Related Weaknesses (CWE)
References
- https://my.f5.com/manage/s/article/K000161019MitigationVendor Advisory
- https://depthfirst.com/nginx-riftMitigationTechnical DescriptionThird Party Advisory
- https://github.com/DepthFirstDisclosures/Nginx-RiftExploitThird Party Advisory
- https://access.redhat.com/errata/RHSA-2026:17417
- https://access.redhat.com/errata/RHSA-2026:17751
- https://access.redhat.com/errata/RHSA-2026:17752
- https://access.redhat.com/errata/RHSA-2026:17753
- https://access.redhat.com/errata/RHSA-2026:17790
- https://access.redhat.com/errata/RHSA-2026:17791
- https://access.redhat.com/errata/RHSA-2026:17792
- https://access.redhat.com/errata/RHSA-2026:17793
- https://access.redhat.com/errata/RHSA-2026:17794
- https://access.redhat.com/errata/RHSA-2026:18029
- https://access.redhat.com/errata/RHSA-2026:18041
- https://access.redhat.com/errata/RHSA-2026:18063
FAQ
What is CVE-2026-42945?
CVE-2026-42945 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ...
How severe is CVE-2026-42945?
CVE-2026-42945 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42945?
Check the references section above for vendor advisories and patch information. Affected products include: F5 Dos, F5 Nginx Gateway Fabric, F5 Nginx Ingress Controller, F5 Nginx Instance Manager, F5 Nginx Open Source.