CVE-2026-56434Patch(f5 / nginx_gateway_fabric)

LOWCVSS 8.3 · HIGH

Signal is active with 2 mentions in latest observed window

Immediate actions

Patch f5 nginx_gateway_fabric systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

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.

f5 CVEs Back to dashboard

1.0/ 10 priority

Sources & remediation

Vendor / third-party advisories

https://my.f5.com/manage/s/article/K000162098

Weakness type (CWE)

CWE-416

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

nginx_gateway_fabric
nginx_ingress_controller
nginx_plus
waf

Threat summary

Patch or workaround signal is available
11 mentions across 6 observed days
Momentum state: stable

What's happening

Patch or workaround mentioned in 6 signals
Technical details provided in 8 signals
Disclosure: 4 classified signals
General: 2 classified signals
Peaked 5d ago at 5 mentions (2026-07-16); latest day: 2
11 total mentions across 6 days

Affected systems

Vendors

Products

nginx_gateway_fabricnginx_ingress_controllernginx_pluswaf

3 versions affected across 4 products

Deep dive

Activity timeline11 mentions / 6d

Signal classification3 categories

Patch

545.5%

Disclosure

436.4%

General

218.2%

Referenced assets8 URLs

By indicator

Classification over time

Date	Total	Labels

2026-07-16	5	Disclosure2Patch3
2026-07-21	1	Disclosure1
2026-07-22	1	Patch1
2026-07-23	1	Patch1
2026-08-25	1	General1
2026-09-12	2	Disclosure1General1

Full discourse11 posts

ZoomEye@zoomeye_team91d
Disclosure
🚨 CVE-2026-56434: NGINX ngx_http_ssi_module vulnerability Critical Vulnerability Alert! Nginx is affected by CVE-2026-56434. Full Vulnerability Details & Analysis at DarkEye: 🔗 https://darkeye.org/vuln/cve/CVE-2026-56434 🔍 Identify Targets via ZoomEye: Filter: vul.cve="CVE-2026-56434" Search Dork: app="Nginx" Exposure: 302.5m instances identified globally. ZoomEye Search Link: 👉 https://www.zoomeye.ai/searchResult?q=YXBwPSJOZ2lueCI=&t=all&utm_source=twitter&utm_medium=social&utm_campaign=cve_ops_20260716 #Infosec #CyberSecurity #ZoomEye #DarkEye
Post summary
The tweet announces the CVE-2026-56434 vulnerability in NGINX’s ngx_http_ssi_module, offers a link to further analysis and highlights widespread exposure via ZoomEye, but provides neither PoC, exploit code, patch information, nor evidence of active exploitation.
219150215.9K
12.7K followersView on X
Daily CyberSecurity@Daily_CyberSec91d
Patch
F5 patched the NGINX code execution flaw CVE-2026-42533, along with CVE-2026-60005 and CVE-2026-56434. Update NGINX Plus and Open Source builds now. #NGINX #CVE202642533 #CodeExecution #F5 #Vulnerability http://securityonline.info/nginx-code-execution-cve-2026-42533/
Post summary
F5 has patched several NGINX code execution vulnerabilities (CVE-2026-42533, CVE-2026-60005, CVE-2026-56434); users are urged to update both NGINX Plus and Open Source builds.
020113712
12.9K followersView on X
Modat@modat_magnify91d
Patch
⚠️NGINX – Multiple Memory-Safety Flaws Patched (CVSS up to 9.2) F5 has patched three memory-safety flaws in NGINX. The most serious CVE-2026-42533 (CVSS 9.2) is a heap buffer overflow in the worker process when the map directive with regex matching references a capture before the map's output variable; a remote attacker can trigger it with crafted HTTP requests, and code execution is possible when ASLR is disabled or bypassed. CVE-2026-56434 is a use-after-free in the SSI filter module, exploitable by an attacker with man-in-the-middle control over upstream responses, enabling limited memory modification or a worker restart. CVE-2026-60005 is an uninitialized memory access in the slice module (not enabled by default) that can cause worker memory disclosure or termination. Affected: NGINX Open Source and NGINX Plus prior to 1.31.3. Mitigation: Upgrade to nginx 1.31.3 or later, and verify your distribution's build includes the fixes rather than trusting the version number alone. Modat Magnify Query: technology="Nginx" The platform: https://magnify.modat.io/ Reference: https://nginx.org/en/security_advisories.html #Modat #ModatMagnify #threatintel #vulnerability #CVE202642533 #CVE202656434 #CVE202660005 #NGINX #infosec #Critical
Post summary
F5 announced patching of three high‑severity memory‑safety flaws in NGINX (CVE‑2026‑42533, CVE‑2026‑56434, CVE‑2026‑60005) with detailed technical information and recommends upgrading to version 1.31.3 or later.
01045444
1.8K followersView on X
Rıdvan Yağlı@ridvanyagli91d
Patch
🔴 NGINX kullanıcılarının dikkatine! F5, NGINX ve NGINX Plus'ı etkileyen 3 yüksek önem dereceli güvenlik açığını duyurdu. • CVE-2026-42533 – Heap Buffer Overflow • CVE-2026-60005 – Uninitialized Memory Disclosure • CVE-2026-56434 – Use-After-Free Etkilenen sistemlerde bellek bozulması, worker process çökmesi ve uygun koşullarda uzaktan kod çalıştırma (RCE) riski bulunuyor. NGINX versiyonlarınızı 1.31.3'e yükseltmeniz önerilir.
Post summary
The post announces three high‑severity CVEs affecting NGINX, describes their technical nature and RCE risk, and urges users to upgrade to version 1.31.3 to mitigate the vulnerabilities.
02022340
2.2K followersView on X
Jangra@jxngrx86d
Disclosure
🚨 @nginxorg users, this is one to prioritize. A critical heap buffer overflow (CVE-2026-42533, CVSS 9.2) has been disclosed in both NGINX Open Source and NGINX Plus. The advisory also patches: • Memory disclosure (CVE-2026-60005) • Use-after-free (CVE-2026-56434) Most deployed NGINX versions are affected. There's no public exploit yet, but history shows it's only a matter of time. If you're running production workloads, upgrade to the latest patched release. #CyberSecurity #NGINX #Linux #DevOps #CloudSecurity #InfoSec #AppSec #OpenSource #SecurityNews #CVE
Post summary
NGINX Open Source and Plus are affected by a critical heap buffer overflow (CVE-2026-42533); users are urged to apply patches and upgrade to the latest release.
2002068
573 followersView on X
Lyrie.ai@lyrie_ai33d
Disclosure
CVE-2026-56434: 🚨 CVE-2026-56434: NGINX ngxhttpssimodule vulnerability Critical Vulnerability Alert! Nginx is affected by CVE-2026-56434. Full Vulnerability Details &amp; Analysis at DarkEye: 🔗 🔍 Identify Targets via ZoomEye: Filter:…
Post summary
The post announces the discovery of CVE-2026-56434 affecting the NGINX ngxhttpssimodule, but provides no technical, exploit, or remediation details.
1000099
325 followersView on X
Lyrie.ai@lyrie_ai33d
General
Source: X search for CVE-2026 critical Posted: 2026-07-16T05:13:44.000Z Likes: 36 0day Intel: 🚨 CVE-2026-56434: NGINX ngxhttpssimodule vulnerability
Post summary
A brief tweet reports the existence of CVE-2026-56434 affecting the NGINX ngxhttpssimodule but provides no further technical or remedial details.
1000083
325 followersView on X
iototsecnews@iototsecnews84d
Patch
NGINX の脆弱性 CVE-2026-56434／42533／60005 が FIX：RCE／メモリ漏洩／DoS の恐れ https://iototsecnews.jp/2026/07/16/f5-fixes-3-nginx-flaws-enabling-potential-remote-code-execution-memory-disclosure-and-dos-attacks/ 今回の 3 件の脆弱性は、 NGINX のリクエスト処理を行うデータ・プレーンに原因があります。最も深刻な CVE-2026-42533 は、マップ・ディレクティブと正規表現の処理方法の不備により、ヒープバッファ・オーバーフローを引き起こすものです。また、2 つ目の CVE-2026-56434 は、特定の SSI 設定時に解放済みメモリの使用を引き起こします。CVE-2026-60005 は slice モジュールで、未初期化メモリへのアクセスを許すという問題を引き起こします。いずれも、特定のモジュール利用や複雑な設定の組み合わせといった、内部の処理ロジックの隙が引き金となっています。ご利用のチームは、ご注意ください。 #CVE202642533 #CVE202656434 #CVE202660005 #F5 #nginx #Vulnerability
Post summary
The article announces that F5 has released fixes for three NGINX vulnerabilities (CVE‑2026‑42533, CVE‑2026‑56434, CVE‑2026‑60005) capable of RCE, memory disclosure, and DoS, and urges teams to apply the patches promptly.
01000145
501 followersView on X
ThreatWire@ThreatWire_90d
Disclosure
🚨 CVE-2026-42533, CVE-2026-60005 & CVE-2026-56434: F5 has disclosed three high-severity vulnerabilities affecting NGINX Plus and NGINX Open Source, potentially leading to memory corruption, worker crashes, or remote code execution. #CyberSecurity #CVE #NGINX #F5 #ThreatWire
Post summary
F5 disclosed three high‑severity CVEs affecting NGINX that could cause memory corruption or remote code execution, but no PoC, exploit code, active exploitation, or patch information is provided.
0001074
114 followersView on X
IntegSec@integ_sec51d
General
CVE-2026-56434: NGINX Server-Side Includes Use-After-Free Bug - What It Means for Your Business and How to Respond https://hubs.li/Q04vbmND0
Post summary
The brief excerpt introduces CVE‑2026‑56434 as a Server‑Side Includes use‑after‑free issue in NGINX and implies a business‑focused response, but lacks specific details about patches, tools, or active exploitation.
0000040
33 followersView on X
Windows Forum@windowsforum85d
Patch
🛠️ NGINX 1.31.3 fixes a Server-Side Includes use-after-free—but only for a very specific proxy setup. Not “the Internet is on fire,” just another reminder that config flags bite. https://windowsforum.com/threads/cve-2026-56434-fix-nginx-ssi-worker-restart-bug-in-1-31-3.439964/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #CveVulnerabilities #NginxSecurity #ServerSideIncludes #WebServerSecurity https://t.co/ezDFcSk2Mj
Post summary
The post announces that NGINX 1.31.3 provides a patch for a Server‑Side Includes use‑after‑free flaw (CVE‑2026‑56434), effective only for a specific proxy setup.
0000026
1.3K followersView on X

CPE platform detail14 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

14 of 14 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	f5	nginx_gateway_fabric	-	-	-
App	f5	nginx_ingress_controller	-	-	-
App	f5	nginx_ingress_controller	-	-	-
App	f5	nginx_ingress_controller	4.0.0	-	-
App	f5	nginx_ingress_controller	4.0.1	-	-
App	f5	nginx_plus	-	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	nginx_plus	r36	-	-
App	f5	waf	-	nginx	-

Explore more

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What researchers are saying

CVE-2026-56434

ZoomEye[verified]@zoomeye_teamDisclosure

The tweet announces the CVE-2026-56434 vulnerability in NGINX’s ngx_http_ssi_module, offers a link to further analysis and highlights widespread exposure via ZoomEye, but provides neither PoC, exploit code, patch information, nor evidence of active exploitation.

Modat[verified]@modat_magnifyPatch

F5 announced patching of three high‑severity memory‑safety flaws in NGINX (CVE‑2026‑42533, CVE‑2026‑56434, CVE‑2026‑60005) with detailed technical information and recommends upgrading to version 1.31.3 or later.

Rıdvan Yağlı[verified]@ridvanyagliPatch

The post announces three high‑severity CVEs affecting NGINX, describes their technical nature and RCE risk, and urges users to upgrade to version 1.31.3 to mitigate the vulnerabilities.

Jangra[verified]@jxngrxDisclosure

NGINX Open Source and Plus are affected by a critical heap buffer overflow (CVE-2026-42533); users are urged to apply patches and upgrade to the latest release.

Lyrie.ai[verified]@lyrie_aiDisclosure

The post announces the discovery of CVE-2026-56434 affecting the NGINX ngxhttpssimodule, but provides no technical, exploit, or remediation details.

Lyrie.ai[verified]@lyrie_aiGeneral

A brief tweet reports the existence of CVE-2026-56434 affecting the NGINX ngxhttpssimodule but provides no further technical or remedial details.

IntegSec[verified]@integ_secGeneral

The brief excerpt introduces CVE‑2026‑56434 as a Server‑Side Includes use‑after‑free issue in NGINX and implies a business‑focused response, but lacks specific details about patches, tools, or active exploitation.

Windows Forum[verified]@windowsforumPatch

The post announces that NGINX 1.31.3 provides a patch for a Server‑Side Includes use‑after‑free flaw (CVE‑2026‑56434), effective only for a specific proxy setup.