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Fencer Vulns
high 8.1

CVE-2026-9256 in the critical feed json

NGINX ngx_http_rewrite_module vulnerability

published 2026-05-22 5 mo ago modified 2026-09-08 2 mo ago also BIT-nginx-2026-9256 , BIT-nginx-gateway-2026-9256 , EUVD-2026-31444

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
10.9%
EPSS 10.9% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl-Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. An unauthenticated attacker along with conditions beyond their 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.

Patch / fix

  • bitnami nginx 1.24.0, 1.30.2, 1.31.1
  • bitnami nginx-gateway 2.2.1
  • F5 NGINX Plus 37.0.1.1, R32 P7, R36 P5
  • F5 NGINX Open Source 1.30.2, 1.31.1
  • Red Hat Red Hat Enterprise Linux 10 2:1.26.3-6.el10_2.4
  • Red Hat Red Hat Enterprise Linux 8 8100020260611094050.489197e6
  • Red Hat Red Hat Enterprise Linux 9 2:1.20.1-28.el9_8.3, 9080020260609152155.9, 9080020260610161820.9
  • Red Hat Red Hat Discovery 2 1782756541
  • Red Hat Red Hat Hardened Images 1.30.2-1.hum1
  • Red Hat Red Hat Update Infrastructure 5 1784794778, 1784794818, 1784795076, 1787241211, 1787241260
  • nginx Debian 12 1.22.1-9+deb12u8
  • nginx Debian 13 1.26.3-3+deb13u6
  • nginx Debian 14 1.30.1-3

debian advisories DEBIAN-CVE-2026-9256

  • nginx Ubuntu 22.04 LTS 1.18.0-6ubuntu14.12
  • nginx Ubuntu 24.04 LTS 1.24.0-2ubuntu7.9
  • nginx Ubuntu 25.10 1.28.0-6ubuntu1.4
  • nginx Ubuntu 26.04 LTS 1.28.3-2ubuntu1.2
  • nginx Ubuntu Pro 14.04 LTS 1.4.6-1ubuntu3.9+esm6
  • nginx Ubuntu Pro 16.04 LTS 1.10.3-0ubuntu0.16.04.5+esm7
  • nginx Ubuntu Pro 18.04 LTS 1.14.0-0ubuntu1.11+esm2
  • nginx Ubuntu Pro 20.04 LTS 1.18.0-0ubuntu1.7+esm1

ubuntu advisories UBUNTU-CVE-2026-9256

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nginx RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-core RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-mod-mail RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-filesystem RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-mod-stream RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-all-modules RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-mod-http-perl RHEL 10.2 2:1.26.3-6.el10_2.4
  • nginx-mod-http-xslt-filter RHEL 10.2 2:1.26.3-6.el10_2.4

red hat advisories RHSA-2026:29874RHSA-2026:29151RHSA-2026:28973RHSA-2026:28921RHSA-2026:28212RHSA-2026:20351

  • nginx SLES for SAP applications 16.0, SLES 16.0 1.27.2-160000.5.1
  • nginx SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 1.21.5-150400.3.20.1
  • nginx SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Server Applications 15 SP7 1.21.5-150600.10.21.1

suse advisories SUSE-SU-2026:22178-1SUSE-SU-2026:2370-1SUSE-SU-2026:2307-1

  • nginx openSUSE Leap 16.0 1.27.2-160000.5.1
  • nginx openSUSE Tumbleweed 1.31.1-1.1

opensuse advisories openSUSE-SU-2026:21107-1openSUSE-SU-2026:10852-1

  • nginx AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-core AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-mod-mail AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-filesystem AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-mod-stream AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-all-modules AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-mod-http-perl AlmaLinux 10 2:1.26.3-6.el10_2.4
  • nginx-mod-http-xslt-filter AlmaLinux 10 2:1.26.3-6.el10_2.4

almalinux advisories ALSA-2026:29874ALSA-2026:28921ALSA-2026:28973ALSA-2026:29151ALSA-2026:28212

  • nginx Rocky Linux 10 2:1.26.3-6.el10_2.4
  • nginx Rocky Linux 9 2:1.26.3-9.module+el9.8.0+40194+40adfc1b
  • nginx Rocky Linux 8 1:1.24.0-3.module+el8.10.0+40187+52bedf24.1
  • nginx Rocky Linux 8 1:1.24.0-3.module+el8.10.0+40144+38158758
  • nginx Rocky Linux 9 1:1.24.0-7.module+el9.8.0+40193+7b2d11e4.1.rocky.0.1

rocky linux advisories RLSA-2026:29874RLSA-2026:29151RLSA-2026:28921RLSA-2026:28212

  • nginx Alpine 3.21 1.26.3-r1
  • nginx Alpine 3.23, Alpine 3.22 1.28.3-r2
  • nginx Alpine 3.24 1.30.2-r0

alpine advisories ALPINE-CVE-2026-9256

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • nginx Azure Linux 3.0 1.28.3-4

azure linux advisories AZL-88116

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-9256 updated cvss 8.1

nginx: ngx_http_rewrite_module: code execution and denial of service

  • Red Hat Lightspeed proxy 1 insights-proxy/insights-proxy-container-rhel9
    affected: workaround, no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) nginx-debuginfo 1.20.1-22.el9_6.7, nginx-mod-devel 1.20.1-22.el9_6.7, nginx-debugsource 1.20.1-22.el9_6.7, nginx-core-debuginfo 1.20.1-22.el9_6.7, nginx-mod-mail-debuginfo 1.20.1-22.el9_6.7, nginx-mod-stream-debuginfo 1.20.1-22.el9_6.7, +3 more
    fixed: vendor fix RHSA-2026:93467
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1782756541
    fixed: vendor fix RHSA-2026:33313
  • Red Hat Enterprise Linux AppStream (v. 8) nginx 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, nginx-mod-mail 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, nginx-filesystem 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, nginx-mod-stream 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, nginx-all-modules 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, nginx-mod-http-perl 1.24.0-3.module+el8.10.0+24380+8b0811ed.2, +2 more
    fixed: vendor fix RHSA-2026:28921
  • Red Hat Enterprise Linux AppStream (v. 9) nginx 1.20.1-28.el9_8.3, nginx-core 1.20.1-28.el9_8.3, nginx-mod-mail 1.20.1-28.el9_8.3, nginx-filesystem 1.20.1-28.el9_8.3, nginx-mod-stream 1.20.1-28.el9_8.3, nginx-all-modules 1.20.1-28.el9_8.3, +21 more
    fixed: vendor fix RHSA-2026:28212
  • Red Hat Enterprise Linux AppStream (v. 10) nginx 1.26.3-6.el10_2.4, nginx-core 1.26.3-6.el10_2.4, nginx-mod-mail 1.26.3-6.el10_2.4, nginx-filesystem 1.26.3-6.el10_2.4, nginx-mod-stream 1.26.3-6.el10_2.4, nginx-all-modules 1.26.3-6.el10_2.4, +3 more
    fixed: vendor fix RHSA-2026:29874
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) nginx 1.20.1-14.el9_2.7, nginx-core 1.20.1-14.el9_2.7, nginx-mod-mail 1.20.1-14.el9_2.7, nginx-filesystem 1.20.1-14.el9_2.7, nginx-mod-stream 1.20.1-14.el9_2.7, nginx-all-modules 1.20.1-14.el9_2.7, +3 more
    fixed: vendor fix RHSA-2026:93472
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) nginx 1.20.1-16.el9_4.7, nginx-core 1.20.1-16.el9_4.7, nginx-mod-mail 1.20.1-16.el9_4.7, nginx-filesystem 1.20.1-16.el9_4.7, nginx-mod-stream 1.20.1-16.el9_4.7, nginx-all-modules 1.20.1-16.el9_4.7, +3 more
    fixed: vendor fix RHSA-2026:93468
show 6 more
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) nginx 1.20.1-22.el9_6.7, nginx-core 1.20.1-22.el9_6.7, nginx-mod-mail 1.20.1-22.el9_6.7, nginx-filesystem 1.20.1-22.el9_6.7, nginx-mod-stream 1.20.1-22.el9_6.7, nginx-all-modules 1.20.1-22.el9_6.7, +3 more
    fixed: vendor fix RHSA-2026:93467
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nginx-debuginfo 1.20.1-28.el9_8.3, nginx-mod-devel 1.20.1-28.el9_8.3, nginx-debugsource 1.20.1-28.el9_8.3, nginx-core-debuginfo 1.20.1-28.el9_8.3, nginx-mod-mail-debuginfo 1.20.1-28.el9_8.3, nginx-mod-stream-debuginfo 1.20.1-28.el9_8.3, +3 more
    fixed: vendor fix RHSA-2026:28973
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nginx-debuginfo 1.26.3-6.el10_2.4, nginx-mod-devel 1.26.3-6.el10_2.4, nginx-debugsource 1.26.3-6.el10_2.4, nginx-core-debuginfo 1.26.3-6.el10_2.4, nginx-mod-mail-debuginfo 1.26.3-6.el10_2.4, nginx-mod-stream-debuginfo 1.26.3-6.el10_2.4, +3 more
    fixed: vendor fix RHSA-2026:29874
  • Red Hat Hardened Images nginx 1.30.2-1.hum1, nginx-core 1.30.2-1.hum1, nginx-mod-mail 1.30.2-1.hum1, nginx-filesystem 1.30.2-1.hum1, nginx-mod-stream 1.30.2-1.hum1, nginx-all-modules 1.30.2-1.hum1, +5 more
    fixed: vendor fix RHSA-2026:20351
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1784794778, rhui5/rhua-rhel9 1784795076, rhui5/rhua-tp-rhel9 1787241260, rhui5/cds-kubernetes-rhel9 1784794818, rhui5/cds-kubernetes-tp-rhel9 1787241211
    fixed: vendor fix RHSA-2026:44481
  • Red Hat Discovery 2 discovery/discovery-server-rhel9 1782763840 Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206, rhui5/haproxy-rhel9 1784795112, rhui5/installer-rhel9 1784794289, rhui5/installer-tp-rhel9 1787135742
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

10.86% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:H/AT:P/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

Affected packages

ecosystem package affected fixed in
bitnami nginx
>=0.1.17, <1.24.0
>=1.30.0, <1.30.2
>=1.31.0, <1.31.1
1.24.0
1.30.2
1.31.1
bitnami nginx-gateway
>=0.1.17, <2.2.1
2.2.1

Affected products

  • F5 NGINX Plus
  • F5 NGINX Open Source
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Discovery 2
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Update Infrastructure 5
  • Red Hat Red Hat Lightspeed proxy 1

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.