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Findings

CVE-2026-27654

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

Published Mar 24, 2026 · updated Jul 15, 2026 · 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.

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.

Affected

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

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