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Fencer Vulns
medium 6.5

CVE-2026-56434 json

NGINX ngx_http_ssi_module vulnerability

published 2026-07-15 3 mo ago modified 2026-09-08 2 mo ago also BIT-nginx-2026-56434 , BIT-nginx-gateway-2026-56434 , EUVD-2026-44684

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX worker process.

Impact: This vulnerability may allow remote attackers to have limited control to modify memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Patch / fix

  • bitnami nginx 1.30.4, 1.31.3
  • bitnami nginx-gateway 1.30.4, 1.31.3
  • F5 NGINX Plus 37.0.3.1, R36 P7
  • F5 NGINX Open Source 1.30.4, 1.31.3
  • nginx Debian 12 1.22.1-9+deb12u10
  • nginx Debian 13 1.26.3-3+deb13u8
  • nginx Debian 14 1.30.1-7

debian advisories DEBIAN-CVE-2026-56434

  • nginx Ubuntu 22.04 LTS 1.18.0-6ubuntu14.17
  • nginx Ubuntu 24.04 LTS 1.24.0-2ubuntu7.14
  • nginx Ubuntu 26.04 LTS 1.28.3-2ubuntu1.7

ubuntu advisories UBUNTU-CVE-2026-56434

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 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-core RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-mod-mail RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-filesystem RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-mod-stream RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-all-modules RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-mod-http-perl RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4
  • nginx-mod-http-xslt-filter RHEL 9 1:1.24.0-7.module+el9.8.0+24626+085354fc.4

red hat advisories RHSA-2026:59490RHSA-2026:59496RHSA-2026:59362RHSA-2026:59216RHSA-2026:59220RHSA-2026:46012

  • nginx openSUSE Tumbleweed 1.31.3-1.1

opensuse advisories openSUSE-SU-2026:11295-1

  • nginx AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-core AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-mod-mail AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-filesystem AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-mod-stream AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-all-modules AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-mod-http-perl AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1
  • nginx-mod-http-xslt-filter AlmaLinux 9 2:1.20.1-28.el9_8.5.alma.1

almalinux advisories ALSA-2026:59362ALSA-2026:59490ALSA-2026:59496ALSA-2026:59216ALSA-2026:59220

  • nginx Rocky Linux 9 2:1.20.1-28.el9_8.5.rocky.0.1
  • nginx Rocky Linux 9 2:1.26.3-9.module+el9.8.0+40235+8be1317a.2
  • nginx Rocky Linux 9 2:1.26.3-9.module+el9.8.0+40222+e48d13b6.1
  • nginx Rocky Linux 9 2:1.26.3-9.module+el9.8.0+40194+40adfc1b
  • nginx Rocky Linux 9 1:1.24.0-7.module+el9.8.0+40193+7b2d11e4.1.rocky.0.1
  • nginx Rocky Linux 9 1:1.24.0-7.module+el9.8.0+40218+76099d32.2.rocky.0.1
  • nginx Rocky Linux 9 1:1.24.0-7.module+el9.8.0+40234+d28db9b8.3.rocky.0.1
  • nginx Rocky Linux 10 2:1.26.3-6.el10_2.6

rocky linux advisories RLSA-2026:59362RLSA-2026:59496RLSA-2026:59490RLSA-2026:59220RLSA-2026:59216

  • nginx Alpine 3.21 1.26.3-r2
  • nginx Alpine 3.23, Alpine 3.22 1.28.3-r6
  • nginx Alpine 3.24 1.30.4-r0

alpine advisories ALPINE-CVE-2026-56434

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 1.28.3-8

azure linux advisories AZL-92496

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-2026-56434 updated cvss 6.5

nginx: NGINX: Heap buffer over-read allows memory modification or 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 1788206196
    fixed: vendor fix RHSA-2026:61783
  • Red Hat Enterprise Linux AppStream (v. 8) nginx 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, nginx-mod-mail 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, nginx-filesystem 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, nginx-mod-stream 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, nginx-all-modules 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, nginx-mod-http-perl 1.24.0-3.module+el8.10.0+24644+2676a8ce.4, +2 more
    fixed: vendor fix RHSA-2026:59216
  • Red Hat Enterprise Linux AppStream (v. 9) nginx 1.20.1-28.el9_8.5, nginx-core 1.20.1-28.el9_8.5, nginx-mod-mail 1.20.1-28.el9_8.5, nginx-filesystem 1.20.1-28.el9_8.5, nginx-mod-stream 1.20.1-28.el9_8.5, nginx-all-modules 1.20.1-28.el9_8.5, +21 more
    fixed: vendor fix RHSA-2026:59490
  • Red Hat Enterprise Linux AppStream (v. 10) nginx 1.26.3-6.el10_2.6, nginx-core 1.26.3-6.el10_2.6, nginx-mod-mail 1.26.3-6.el10_2.6, nginx-filesystem 1.26.3-6.el10_2.6, nginx-mod-stream 1.26.3-6.el10_2.6, nginx-all-modules 1.26.3-6.el10_2.6, +3 more
    fixed: vendor fix RHSA-2026:59220
  • 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_8.5, nginx-mod-devel 1.20.1-28.el9_8.5, nginx-debugsource 1.20.1-28.el9_8.5, nginx-core-debuginfo 1.20.1-28.el9_8.5, nginx-mod-mail-debuginfo 1.20.1-28.el9_8.5, nginx-mod-stream-debuginfo 1.20.1-28.el9_8.5, +3 more
    fixed: vendor fix RHSA-2026:59362
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nginx-debuginfo 1.26.3-6.el10_2.6, nginx-mod-devel 1.26.3-6.el10_2.6, nginx-debugsource 1.26.3-6.el10_2.6, nginx-core-debuginfo 1.26.3-6.el10_2.6, nginx-mod-mail-debuginfo 1.26.3-6.el10_2.6, nginx-mod-stream-debuginfo 1.26.3-6.el10_2.6, +3 more
    fixed: vendor fix RHSA-2026:59220
  • Red Hat Hardened Images nginx 1.30.4-2.hum1, nginx-core 1.30.4-2.hum1, nginx-mod-mail 1.30.4-2.hum1, nginx-filesystem 1.30.4-2.hum1, nginx-mod-stream 1.30.4-2.hum1, nginx-all-modules 1.30.4-2.hum1, +5 more
    fixed: vendor fix RHSA-2026:46012
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1788880464, rhui5/rhua-rhel9 1788880581, rhui5/cds-kubernetes-rhel9 1788880445
    fixed: vendor fix RHSA-2026:66018
  • Red Hat Discovery 2 discovery/discovery-server-rhel9 1788205779 Red Hat Hardened Images php 8.5.8-2.hum1 Red Hat Update Infrastructure 5 rhui5/haproxy-rhel9 1788880456, rhui5/installer-rhel9 1788765051
    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
partial
Assessed
3 mo ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/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
>=0.8.11, <1.30.4
>=1.31.0, <1.31.3
1.30.4
1.31.3
bitnami nginx-gateway
>=0.8.11, <1.30.4
>=1.31.0, <1.31.3
1.30.4
1.31.3

Affected products

  • F5 NGINX Plus
  • F5 NGINX Open Source

Classification

Weakness
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.