CVE-2026-27654

HIGH

NGINX ngx_http_dav_module vulnerability

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2026-27654. PoCs published by XZ1r0, JohannesLks.

AI-analyzed exploit summary This repository contains a functional Python PoC for CVE-2026-27654, a heap buffer overflow in nginx's ngx_http_dav_module caused by a size_t underflow. The exploit sends a crafted MOVE request to trigger the vulnerability, leading to a worker process crash (DoS).

Description

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.

Exploits (2)

github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/web/CVE-2026-27654

This repository contains a functional Python PoC for CVE-2026-27654, a heap buffer overflow in nginx's ngx_http_dav_module caused by a size_t underflow. The exploit sends a crafted MOVE request to trigger the vulnerability, leading to a worker process crash (DoS).

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: nginx 0.5.13 through 1.28.2 (stable) and 1.29.0 through 1.29.6 (mainline)
No auth needed
Prerequisites: nginx compiled with --with-http_dav_module · location block using alias (not root) · dav_methods includes COPY or MOVE
devstral-2 · analyzed May 21, 2026 Full analysis →
nomisec WORKING POC
by JohannesLks · poc
https://github.com/JohannesLks/CVE-2026-27654

This repository contains a functional exploit PoC for CVE-2026-27654, a heap buffer overflow in NGINX's `ngx_http_dav_module` caused by a `size_t` underflow when processing crafted `MOVE` or `COPY` requests. The PoC demonstrates the vulnerability by triggering a crash in vulnerable NGINX versions (0.5.13 through 1.28.2 and 1.29.0 through 1.29.6) compiled with `--with-http_dav_module` and using `alias` in the DAV location.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: NGINX 0.5.13 through 1.28.2 (stable) and 1.29.0 through 1.29.6 (mainline)
No auth needed
Prerequisites: NGINX compiled with `--with-http_dav_module` · DAV location configured with `alias` · DAV methods include `COPY` or `MOVE`
devstral-2 · analyzed Apr 09, 2026 Full analysis →

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
https://my.f5.com/manage/s/article/K000160382

Scores

CVSS v3 8.2
EPSS 0.0002
EPSS Percentile 6.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-122
Status published
Products (13)
F5/NGINX Open Source 0.5.13 - 1.28.3
F5/NGINX Open Source 1.29.0 - 1.29.7
F5/NGINX Plus R32 - R32 P5
F5/NGINX Plus R33
F5/NGINX Plus R34
F5/NGINX Plus R35 - R35 P2
F5/NGINX Plus R36 - R36 P3
f5/nginx_open_source 0.5.13 - 0.9.7
f5/nginx_plus r32 p1 (4 CPE variants)
f5/nginx_plus r33 (4 CPE variants)
... and 3 more
Published Mar 24, 2026
Tracked Since Mar 24, 2026