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Nginx PlusWeb server / proxy · F5

CVE-2026-27654

HIGH · 8.2 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 →
91/100
Remediation priority · Urgent
Remotely reachable No privileges 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
NGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_dav_module module that might allow an attacker to trigger a buffer overflow to the NGINX worker process; this vulnerability may result in termination of the NGINX worker process or modification of source or destination file names outside the document root. This issue affects NGINX Open Source and NGINX Plus when the configuration file uses DAV module MOVE or COPY methods, prefix location (nonregular expression location configuration), and alias directives. The integrity impact is constrained because the NGINX worker process user has low privileges and does not have access to the entire system. 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 buffer overflow vulnerability in NGINX's ngx_http_dav_module allows attackers to crash the worker process or manipulate file names outside the document root. Exploitation requires DAV MOVE/COPY methods, prefix location directives, and alias configuration. The attacker's impact is limited by the low-privilege worker process user.

MitigationReview NGINX configurations for DAV module usage with prefix locations and alias directives; either disable unused DAV methods, apply stricter access controls, or upgrade to a patched NGINX version.

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 PlusWeb server / proxy
Affected:= r32= r33= r34= r35= r36
Nginx Open SourceWeb server / proxy
Affected:>= 0.5.13, <= 0.9.7>= 1.0.0, < 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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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. Check NGINX version against affected ranges
    Run 'nginx -v' or 'nginx -V' to get the installed version. Compare with: F5 Nginx Plus r32-r36, or Nginx Open Source 0.5.13-0.9.7, 1.0.0-1.28.2, 1.29.0-1.29.6
    Affected if Installed version falls within any of the affected ranges listed
  2. Verify ngx_http_dav_module is loaded
    Run 'nginx -V 2>&1 | grep -o dav' or check for 'load_module' directives in nginx.conf referencing ngx_http_dav_module.so
    Affected if The dav_module is compiled in or dynamically loaded
  3. Identify locations with DAV methods configured
    Search nginx.conf and included files for 'dav_methods' directive, looking for MOVE or COPY methods (e.g., 'dav_methods PUT DELETE MOVE COPY')
    Affected if DAV MOVE or COPY methods are explicitly allowed in any location block
  4. Check for prefix location blocks
    Search nginx.conf for 'location' blocks with prefix matching (e.g., 'location /prefix', 'location ^~ /prefix') that also contain a 'dav_methods' directive with MOVE or COPY
    Affected if A prefix location block has DAV MOVE or COPY methods configured
  5. Verify alias directive in vulnerable location
    Within any prefix location that has DAV MOVE/COPY enabled, check if an 'alias' directive is present (e.g., 'alias /path/to/files/;')
    Affected if An 'alias' directive is used within a prefix location that has DAV MOVE or COPY methods enabled

The environment is affected if NGINX version is in the affected range AND ngx_http_dav_module is loaded AND DAV MOVE/COPY methods are allowed in a location block that uses both prefix matching and an alias directive.

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

Review NGINX configurations for DAV module usage with prefix locations and alias directives; either disable unused DAV methods, apply stricter access controls, or upgrade to a patched NGINX version.

Recommended fix High confidence

NGINX Open Source: 1.28.3+ or 1.29.7+ | NGINX Plus: r36

  1. 1. Identify the currently installed NGINX version using 'nginx -v' or 'nginx -V'
  2. 2. For NGINX Open Source: determine if running version is in an affected branch (0.5.13-0.9.7, 1.0.0-1.28.2, or 1.29.0-1.29.6)
  3. 3. For NGINX Plus: check if running r32, r33, r34, or r35
  4. 4. For NGINX Open Source: upgrade to version 1.28.3 or higher (if on 1.28.x), or 1.29.7 or higher (if on 1.29.x)
  5. 5. For NGINX Plus: upgrade to r36 or later
  6. 6. Verify the upgrade was successful by checking 'nginx -v' output
  7. 7. Test that NGINX starts properly and the DAV functionality works as expected
  8. 8. Review nginx.conf to ensure DAV module configurations (MOVE, COPY methods with alias directives in prefix locations) are still needed; consider disabling if not required
Caveat None expected - this is a bug fix release; however, verify any custom module compatibility with the new version before deploying to production

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

Fix this in Nginx Plus Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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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-2026-27654 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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