Exploitation reportedNot in CISA KEV yetFix available

CVE-2026-42945

Exploitation reported by one source. First attested on 2026-05-19 by GCVE · kevintel.

Published2026-05-13
WeaknessCWE-122 · CWE-131

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2026-05-1316:16CVE publishedNVD
2026-05-1915:36Listed as exploited by GCVEGCVE
2026-05-1915:36Exploitation first reportedGCVE

Observed activity

isMalicious corpus · updated 2026-10-23 15:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-42945?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-42945?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

F5 nginx ingress controller

Branch	Affected	Fixed in	Source
3.x	≥ 3.5.0, ≤ 3.7.2	no fix published	NVD
4.0	≥ 4.0.0, ≤ 4.0.1	no fix published	NVD
5.x	≥ 5.0.0, ≤ 5.4.1	no fix published	NVD

F5 waf

Branch	Affected	Fixed in	Source
4.x	≥ 4.9.0, ≤ 4.16.0	no fix published	NVD
5.x	≥ 5.1.0, ≤ 5.8.0	no fix published	NVD
5.x	≥ 5.9.0, ≤ 5.12.1	no fix published	NVD

F5 dos

Branch	Affected	Fixed in	Source
4.x	≥ 4.3.0, ≤ 4.7.0	no fix published	NVD
4.8	= 4.8.0	no fix published	NVD

6 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

nginxAlmaLinux:10all versions · fixed in 2:1.26.3-6.el10_2.3and 9 other packages
nginxAlmaLinux:9all versions · fixed in 2:1.20.1-28.el9_8.2.alma.1and 9 other packages
nginxAlmaLinux:8all versions · fixed in 1:1.24.0-3.module_el8.10.0+4182+ca797750.1.alma.1and 8 other packages

Vendor advisories

CVE-2026-42945 Red Hat Product Security1,076 products fixed
nginx: NGINX: Arbitrary Code Execution Vulnerability
RHSA-2026:58981 Red Hat Product Security2 products fixed
Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 Technology Preview security update
ICSA-26-188-03 CISA3 known affected
Hitachi Energy e-mesh EMS
e-mesh EMS versions 4.1.6 · e-mesh EMS versions 4.4.2 · e-mesh EMS versions 4.7.0
RHSA-2026:22396 Red Hat Product Security9 products fixed
Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.14.33 security, enhancement & bug fix update
RHSA-2026:22394 Red Hat Product Security9 products fixed
Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.16.29 security, enhancement & bug fix update
RHSA-2026:22393 Red Hat Product Security9 products fixed
Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.15.29 security, enhancement & bug fix update

24 more advisories

Full record on NVD

Fix

Vendor fix Red Hat Product Security RHSA-2026:58981 · 2 productsPlease consult the RHUI Technology Preview Release Notes at https://access.redhat.com/articles/7141172 for instructions on how to use this image set.
Vendor fix CISA ICSA-26-188-03 · 3 productsApply hotfix for respective e-mesh EMS versions to update NGINX to either v1.30.2 or latest
Vendor fix Red Hat Product Security RHSA-2026:22396 · 9 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.14/html/updating_openshift_data_foundation/updating-ocs-…
Vendor fix Red Hat Product Security RHSA-2026:22394 · 9 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.16/html/updating_openshift_data_foundation/updating-ocs-…
Vendor fix Red Hat Product Security RHSA-2026:22393 · 9 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.15/html/updating_openshift_data_foundation/updating-ocs-…
Vendor fix Red Hat Product Security RHSA-2026:22390 · 9 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.17/html/updating_openshift_data_foundation/updating-ocs-…

Advisories and patches

my.f5.comMitigation · Vendor Advisory
depthfirst.comMitigation

Detection

read 2026-10-23 18:48 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 20 repositories, unverifiedfriparia/NGINX_RIFT_SCAN_CVE_2026_42945p3Nt3st3r-sTAr/CVE-2026-42945-POCrealityone/cve-2026-42945-scancipherspy/CVE-2026-42945-POCnanwinata/nginxrift-CVE-2026-42945

Sources

NVDCVE recordread 2026-10-23
GCVEexploitation2026-05-19
CISA-ADPSSVC decisionnone2026-05-13
OpenCVESSVC decisionnone—
CNACVSS 4.09.2read 2026-10-23
CNACVSS 3.18.1read 2026-10-23
CNAweakness (CWE)CWE-122, CWE-131read 2026-10-23
FIRST EPSSEPSS score3.4 %2026-10-22
PoC-in-GitHubproof of concept20read 2026-10-23
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0 vector: 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/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:X
Published: 2026-05-13
Last Modified: 2026-09-10
NVD status: Modified
MSRC Title: NGINX ngx_http_rewrite_module vulnerability

Frequently asked questions

What is CVE-2026-42945?

Is CVE-2026-42945 actively exploited?

Active exploitation of CVE-2026-42945 has not been confirmed. Its EPSS score was 3.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-42945?

CVE-2026-42945 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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