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TI-2026-30813 Aliases CVE-2026-42533GHSA-fxfg-v4rj-hp95

NGINX Map directive and Regex matching vulnerability

Priority HIGH 75CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 11 fixed, 1 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.

Summary

A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. 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. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. 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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.06296 93rd percentileScored 2026-11-07
Fix Partial NGINX Plus (F5): 37.0.3.1, R36 P7NGINX Open Source (F5): 1.31.3, 1.30.4Red Hat: 10 advisoriesRed Hat: 11 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
F5NGINX Plus37.0.0.1 to before 37.0.3.1; R36 to before R36 P7; R33 and later37.0.3.1, R36 P7Patch availableCNA
F5NGINX Open Source1.31.2 to before 1.31.3; 0.9.6 to before 1.30.41.31.3, 1.30.4Patch availableCNA
  • NGINX Plus VendorF5 Affected 37.0.0.1 to before 37.0.3.1; R36 to before R36 P7; R33 and later Fixed in 37.0.3.1, R36 P7 Patch available CNA
  • NGINX Open Source VendorF5 Affected 1.31.2 to before 1.31.3; 0.9.6 to before 1.30.4 Fixed in 1.31.3, 1.30.4 Patch available CNA

CPE configurations NVD · 14

CPEVersionsRoleVendor
cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*1.3.0 – 1.6.2; 2.0.0 to before 2.6.7VulnerableF5
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:continuous_releases:*:*:*3.5.0 – 3.7.2; 5.0.0 to before 5.5.3VulnerableF5
cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:long-term_support:*:*:*2026-lts-r1 to before 2026-lts-r4VulnerableF5
cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:continuous_releases:*:*:*4.0.0VulnerableF5
cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:continuous_releases:*:*:*4.0.1VulnerableF5
cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*37.0.0.1 to before 37.0.3.1; r33 to before r36VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:*r36VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*r36 p1VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*r36 p2VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:p3:*:*:*:*:*:*r36 p3VulnerableF5
  • cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* Versions 1.3.0 – 1.6.2; 2.0.0 to before 2.6.7 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:continuous_releases:*:*:* Versions 3.5.0 – 3.7.2; 5.0.0 to before 5.5.3 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:long-term_support:*:*:* Versions 2026-lts-r1 to before 2026-lts-r4 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:continuous_releases:*:*:* Versions 4.0.0 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:continuous_releases:*:*:* Versions 4.0.1 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:* Versions 37.0.0.1 to before 37.0.3.1; r33 to before r36 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:* Versions r36 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:* Versions r36 p1 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:* Versions r36 p2 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:p3:*:*:*:*:*:* Versions r36 p3 Vulnerable ·F5
Show 4 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:f5:nginx_plus:r36:p4:*:*:*:*:*:*r36 p4VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:p5:*:*:*:*:*:*r36 p5VulnerableF5
cpe:2.3:a:f5:nginx_plus:r36:p6:*:*:*:*:*:*r36 p6VulnerableF5
cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*4.11.0 – 4.16.0; 5.2.0 – 5.8.0; 5.9.0 to before 5.13.4VulnerableF5
  • cpe:2.3:a:f5:nginx_plus:r36:p4:*:*:*:*:*:* Versions r36 p4 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:p5:*:*:*:*:*:* Versions r36 p5 Vulnerable ·F5
  • cpe:2.3:a:f5:nginx_plus:r36:p6:*:*:*:*:*:* Versions r36 p6 Vulnerable ·F5
  • cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* Versions 4.11.0 – 4.16.0; 5.2.0 – 5.8.0; 5.9.0 to before 5.13.4 Vulnerable ·F5

Remediation

  • Fix · CNA NGINX Plus (F5) Fixed in 37.0.3.1, R36 P7
  • Fix · CNA NGINX Open Source (F5) Fixed in 1.31.3, 1.30.4

Red Hat 10 advisories

  • RHSA-2026:93467 Released 2026-11-02 · Red Hat rating Important
    nginx security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) nginx-mod-devel-2:1.20.1-22.el9_6.7
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) nginx-2:1.20.1-22.el9_6.7, nginx-all-modules-2:1.20.1-22.el9_6.7, nginx-core-2:1.20.1-22.el9_6.7 +6
  • RHSA-2026:93468 Released 2026-11-02 · Red Hat rating Important
    nginx security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) nginx-1:1.20.1-16.el9_4.7, nginx-all-modules-1:1.20.1-16.el9_4.7, nginx-core-1:1.20.1-16.el9_4.7 +6
  • RHSA-2026:93472 Released 2026-11-02 · Red Hat rating Important
    nginx security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) nginx-1:1.20.1-14.el9_2.7, nginx-all-modules-1:1.20.1-14.el9_2.7, nginx-core-1:1.20.1-14.el9_2.7 +6
Show 7 more Red Hat advisories
  • RHSA-2026:79357 Released 2026-10-08 · Red Hat rating Important
    Red Hat Cost Management On-Premise container image update
    • Red Hat Cost Management On-Premise 1 registry.redhat.io/costmanagement/costmanagement-ui-rhel10
  • RHSA-2026:67308 Released 2026-09-14 · Red Hat rating Moderate
    nginx:1.24 security update
    • Red Hat Enterprise Linux AppStream (v. 9) nginx-1:1.24.0-7.module+el9.8.0+24846+e7eec568.5.aarch64::nginx:1.24, nginx-1:1.24.0-7.module+el9.8.0+24846+e7eec568.5.ppc64le::nginx:1.24, nginx-1:1.24.0-7.module+el9.8.0+24846+e7eec568.5.s390x::nginx:1.24 +32
  • RHSA-2026:67314 Released 2026-09-14 · Red Hat rating Important
    nginx security update
    • Red Hat Enterprise Linux AppStream (v. 10) nginx-2:1.26.3-6.el10_2.7, nginx-all-modules-2:1.26.3-6.el10_2.7, nginx-core-2:1.26.3-6.el10_2.7 +6
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nginx-mod-devel-2:1.26.3-6.el10_2.7
  • RHSA-2026:67315 Released 2026-09-14 · Red Hat rating Moderate
    nginx:1.24 security update
    • Red Hat Enterprise Linux AppStream (v. 8) nginx-1:1.24.0-3.module+el8.10.0+24848+0300f002.5.aarch64::nginx:1.24, nginx-1:1.24.0-3.module+el8.10.0+24848+0300f002.5.ppc64le::nginx:1.24, nginx-1:1.24.0-3.module+el8.10.0+24848+0300f002.5.s390x::nginx:1.24 +28
  • RHSA-2026:67283 Released 2026-09-14 · Red Hat rating Moderate
    nginx:1.26 security update
    • Red Hat Enterprise Linux AppStream (v. 9) nginx-2:1.26.3-9.module+el9.8.0+24845+a897661e.4.aarch64::nginx:1.26, nginx-2:1.26.3-9.module+el9.8.0+24845+a897661e.4.ppc64le::nginx:1.26, nginx-2:1.26.3-9.module+el9.8.0+24845+a897661e.4.s390x::nginx:1.26 +32
  • RHSA-2026:66542 Released 2026-09-11 · Red Hat rating Important
    nginx security update
    • Red Hat Enterprise Linux AppStream (v. 9) nginx-2:1.20.1-28.el9_8.6, nginx-all-modules-2:1.20.1-28.el9_8.6, nginx-core-2:1.20.1-28.el9_8.6 +6
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nginx-mod-devel-2:1.20.1-28.el9_8.6
  • RHSA-2026:46012 Released 2026-07-26 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images nginx-2:1.30.4-2.hum1@aarch64, nginx-2:1.30.4-2.hum1@src, nginx-2:1.30.4-2.hum1@x86_64 +22

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    F5 NGINX Plus 37.0.3.1, R36 P7

    4 records Highest priority Priority HIGH 1 HIGH, 1 MEDIUM, 2 LOW

    Other records, highest priority first

    • TI-2026-42786 NGINX ngx_http_slice_module vulnerabilityPriority MEDIUM 45
    • TI-2026-40780 NGINX ngx_http_ssi_module vulnerabilityPriority LOW 37
    • TI-2026-42806 NGINX Plus ngx_stream_mqtt_filter_module vulnerabilityPriority LOW 28
    Show all 4 records →
  • Release ·

    F5 NGINX Open Source 1.30.4, 1.31.3

    3 records Highest priority Priority HIGH 1 HIGH, 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-42786 NGINX ngx_http_slice_module vulnerabilityPriority MEDIUM 45
    • TI-2026-40780 NGINX ngx_http_ssi_module vulnerabilityPriority LOW 37
    Show all 3 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Lightspeed proxy 1AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:93467
Red Hat Cost Management On-Premise 1Fixed RHSA-2026:79357
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:67314
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:67315
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:66542, RHSA-2026:67283, RHSA-2026:67308
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:93472
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:93468
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:93467
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:67314
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:66542
Red Hat Hardened ImagesFixed RHSA-2026:46012
Not affected: 1 product
  • Red Hat Hardened Images

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42533
  2. 2026-10-03 Alias added: GHSA-fxfg-v4rj-hp95
  3. 2026-10-09 Fix available: RHSA-2026:79357 · Red Hat
  4. 2026-10-09 Fix available: Red Hat Cost Management On-Premise 1 · Red Hat
  5. 2026-11-01 EPSS moved to the 90th–95th percentile
  6. 2026-11-02 Fix available: RHSA-2026:93468 · Red Hat
  7. 2026-11-02 Fix available: RHSA-2026:93472 · Red Hat
  8. 2026-11-02 Fix available: RHSA-2026:93467 · Red Hat
  9. 2026-11-02 Fix available: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux AppStream E4S (v.9.4) +1 · Red Hat
  10. 2026-11-03 CISA SSVC decision points changed

References

Patch 1

  • TI-2026-31136 NGINX ngx_http_rewrite_module vulnerability CVSS 4.0CRITICAL 9.2
  • TI-2026-08132 NGINX ngx_http_rewrite_module vulnerability CVSS 4.0CRITICAL 9.2
  • TI-2026-30812 NGINX Open-Source ngx_http_v3_module vulnerability CVSS 4.0CRITICAL 9.2
  • TI-2026-30432 NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability CVSS 4.0CRITICAL 9.2
  • TI-2026-42786 NGINX ngx_http_slice_module vulnerability CVSS 4.0HIGH 8.8
  • TI-2026-36891 NGINX Gateway Fabric vulnerability CVSS 4.0HIGH 8.6
See all 17 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences