CVEs / CVE-2026-42945
CVE-2026-42945: F5 NGINX Plus vulnerability
- critical 9.2 CVSS 4.0 (from the CNA)
- EPSS 68% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| F5 NGINX Plus | from R36, before R36 P4 | R36 P4 |
| F5 NGINX Plus | from R32, before R32 P6 | R32 P6 |
| F5 NGINX Open Source | from 0.6.27, before 1.30.1 | 1.30.1 |
Exploitation
Not in the CISA Known Exploited Vulnerabilities catalog as of 30 Oct 2026.
Severity
| CVSS 4.0 | 9.2 criticalCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-122, CWE-131 |
References
- CVE-2026-42945 on NVD
- CVE-2026-42945 on OSV
- https://my.f5.com/manage/s/article/K000161019 Mitigation, Vendor Advisory
- https://depthfirst.com/nginx-rift Mitigation, Technical Description, Third Party Advisory
- https://github.com/DepthFirstDisclosures/Nginx-Rift Exploit, Third 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
- https://access.redhat.com/errata/RHSA-2026:19159
- https://access.redhat.com/errata/RHSA-2026:19371
- https://access.redhat.com/errata/RHSA-2026:19372
- https://access.redhat.com/errata/RHSA-2026:19374
- https://access.redhat.com/errata/RHSA-2026:20442
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.