Nginx Gateway FabricWeb server / proxy · F5
CVE-2026-42926
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedWhen NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis vulnerability affects NGINX Open Source when configured with proxy_http_version 2 for HTTP/2 proxying combined with the proxy_set_body directive. An attacker can inject malicious HTTP/2 frame headers and payload bytes into the upstream connection, potentially allowing stream manipulation or injection of arbitrary content to the backend server.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Nginx Gateway FabricWeb server / proxy
>= 1.3.0, <= 1.6.2>= 2.0.0, <= 2.6.0
Nginx Open SourceWeb server / proxy
>= 1.29.4, <= 1.30.0
Nginx Instance ManagerWeb server / proxy
>= 2.16.0, <= 2.22.0
Nginx Ingress ControllerWeb server / proxy
>= 3.5.0, <= 3.7.2>= 4.0.0, <= 4.0.1>= 5.0.0, <= 5.4.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed NGINX versionRun 'nginx -v' or 'nginx -V' to determine the installed version. For F5 products, check the specific product version using its respective command or interface.Affected if The version falls within any of these ranges: Nginx Open Source >= 1.29.4 to <= 1.30.0; Nginx Gateway Fabric >= 1.3.0 to <= 1.6.2 or >= 2.0.0 to <= 2.6.0; Nginx Instance Manager >= 2.16.0 to <= 2.22.0; Nginx Ingress Controller >= 3.5.0 to <= 3.7.2, >= 4.0.0 to <= 4.0.1, or >= 5.0.0 to <= 5.4.2
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Identify proxy_http_version 2 configurationSearch nginx configuration files for 'proxy_http_version 2;' using 'grep -r "proxy_http_version 2" /etc/nginx/' or similar search across all .conf files.Affected if The directive 'proxy_http_version 2;' is present in any server or location block.
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Identify proxy_set_body directive usageSearch nginx configuration files for 'proxy_set_body' using 'grep -r "proxy_set_body" /etc/nginx/' or similar search across all .conf files.Affected if The directive 'proxy_set_body' is present in any server or location block.
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Verify both directives in same contextExamine the nginx configuration to determine if both 'proxy_http_version 2' and 'proxy_set_body' appear within the same server block, location block, or upstream block. Review the full configuration context for each occurrence.Affected if Both directives are configured within the same configuration context (server, location, or upstream block), enabling HTTP/2 proxying with body manipulation.
A defender is affected if their NGINX version is in the affected ranges AND both proxy_http_version 2 and proxy_set_body directives are configured together in the same configuration context.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedReview NGINX configurations for the combination of proxy_http_version 2 and proxy_set_body directives; either upgrade to a patched NGINX version or restructure the configuration to avoid this specific combination.
Next stable release beyond each affected version (e.g., Nginx Open Source 1.30.1+, Gateway Fabric 1.6.3+/2.6.1+, Instance Manager 2.23.0+, Ingress Controller 3.7.3+/4.0.2+/5.4.3+)
- 1. Identify the specific Nginx product and current version from the affected versions list
- 2. For Nginx Open Source: upgrade to version 1.30.1 or later
- 3. For Nginx Gateway Fabric: upgrade to version 1.6.3 or later (for 1.x branch) OR version 2.6.1 or later (for 2.x branch)
- 4. For Nginx Instance Manager: upgrade to version 2.23.0 or later
- 5. For Nginx Ingress Controller: upgrade to version 3.7.3 or later (for 3.x branch), OR version 4.0.2 or later (for 4.x branch), OR version 5.4.3 or later (for 5.x branch)
- 6. After upgrade, verify that proxy_http_version 2 and proxy_set_body configurations work as expected
- 7. Test the HTTP/2 proxy functionality to confirm the vulnerability is remediated
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Nginx Gateway Fabric
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42926 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42926 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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