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Vulnerabilities

Vulnerability · CVE-2026-27654

ZDI-26-578: NGINX HTTP Dav Module Alias Directive Integer Underflow Remote Code Execution Vulnerability

Published Mar 24, 2026 · catalog updated Jul 15, 2026 · nginx plus

Check this week

CVE-2026-27654 is not in CISA KEV. FIRST estimates a 25.07% chance of exploitation in the next 30 days. Check whether you run nginx plus.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
25.07%
Remediation
Advisory link
Affected products
cpe f5/nginx open source · cpe f5/nginx plus

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe f5/nginx open sourceversion unspecified
  • cpe f5/nginx plusr32
  • cpe f5/nginx plusr33

How to fix CVE-2026-27654

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-27654 is not in CISA KEV. FIRST estimates a 25.07% chance of exploitation in the next 30 days. Check whether you run nginx plus.

Which versions are affected?

Compare what you have installed with f5/nginx plus r32; f5/nginx plus r33. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-120: Classic Buffer Overflow; CWE-122: Heap-based Buffer Overflow. EPSS 25.07%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Nginx security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 15, 2026 · NIST NVD

    Updated

    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 configuratio

  2. Aug 13, 2026 · Catalog

    Detected

    This vulnerability allows remote attackers to execute arbitrary code on affected installations of NGINX. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 8.1. The following CVEs are assigned: CVE-2026-27654.

Sources

  • CVE.orgVulnerability recordCVE-2026-27654

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27654

    30-day exploitation probability 25.1%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27654

    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 des

    nvd.nist.gov
  • Zero Day InitiativeCoordinated disclosureZDI-26-578

    This vulnerability allows remote attackers to execute arbitrary code on affected installations of NGINX. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 8.1. The following CVEs are assigned: CVE-2026-27654.

    zerodayinitiative.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.