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Nginx Open SourceWeb server / proxy · F5

CVE-2026-27784

HIGH · 7.8 CVSS v3.1 Published 2026-03-24
Fix available
A fix is available. Upgrade to 1.28.3 / 1.29.7 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the attack is possible only if an attacker can trigger the processing of a specially crafted MP4 file with the ngx_http_mp4_module module. 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 · high confidence

A memory over-read/write vulnerability in the 32-bit ngx_http_mp4_module of NGINX Open Source allows attackers to crash the worker process by supplying a specially crafted MP4 file. The flaw only affects 32-bit NGINX builds compiled with ngx_http_mp4_module where the mp4 directive is actively used in the configuration.

MitigationRemediate by either upgrading to a patched NGINX version, switching to 64-bit NGINX, or disabling the mp4 directive in the configuration if the module is not required.

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 Open SourceWeb server / proxy
Affected:>= 1.1.19, < 1.28.3>= 1.29.0, < 1.29.7

CVSS 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify ngx_http_mp4_module is loaded
    Run 'nginx -V 2>&1' and look for 'ngx_http_mp4_module' in the compiled-in modules list
    Affected if The module appears in the output (module is compiled in)
  2. Confirm mp4 directive is in use
    Search your NGINX configuration files for 'mp4' directives (e.g., grep -r 'mp4' /etc/nginx/ or your config directory)
    Affected if The mp4 directive is found within a server or location block in your active configuration
  3. Check installed NGINX version
    Run 'nginx -v' to obtain the exact version number
    Affected if Version is 1.1.19 or higher but below 1.28.3, OR version 1.29.0 or higher but below 1.29.7
  4. Determine NGINX binary architecture
    Run 'file $(which nginx)' or check the NGINX -V output for 32-bit indicators
    Affected if The NGINX binary is 32-bit (the vulnerability only affects 32-bit builds)

You are affected if ngx_http_mp4_module is loaded, the mp4 directive is actively used in your configuration, NGINX is a 32-bit build, and the version falls within the affected ranges (1.1.19 - 1.28.3 or 1.29.0 - 1.29.7).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 1.28.3 / 1.29.7 or later
Fixed in 1.28.31.29.7
Interim mitigation

Remediate by either upgrading to a patched NGINX version, switching to 64-bit NGINX, or disabling the mp4 directive in the configuration if the module is not required.

Recommended fix High confidence

nginx 1.29.7 (or 1.28.3 for 1.28.x line)

  1. 1. Identify current nginx version using 'nginx -v' or 'nginx -V'
  2. 2. If running a 32-bit nginx build with ngx_http_mp4_module enabled and mp4 directive in use, plan upgrade
  3. 3. For version 1.1.19 to 1.28.x: upgrade to nginx 1.28.3
  4. 4. For version 1.29.x: upgrade to nginx 1.29.7
  5. 5. Alternatively, disable the ngx_http_mp4_module entirely if MP4 processing is not required by commenting out or removing the 'mp4' directive in nginx.conf
  6. 6. After upgrade, test nginx starts successfully and validate configuration with 'nginx -t'
  7. 7. Monitor worker processes for unexpected termination after deploying to production
Caveat Review nginx changelog for any breaking changes between current and target version; test in staging first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Nginx Open Source Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,880.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-27784 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data