NGINX DAV Module Buffer Overflow via MOVE/COPY
CVE-2026-27654 Published on March 24, 2026

NGINX ngx_http_dav_module vulnerability
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.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-27654 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
LOW
Availability Impact:
HIGH

Weakness Types

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

What is a Classic Buffer Overflow Vulnerability?

The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. A buffer overflow condition exists when a program attempts to put more data in a buffer than it can hold, or when a program attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the program copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.

CVE-2026-27654 has been classified to as a Classic Buffer Overflow vulnerability or weakness.


Products Associated with CVE-2026-27654

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-27654 are published in these products:

F5 Networks Nginx Open Source
 
F5 Networks Nginx Plus
 
Canonical Ubuntu Linux
 
Red Hat Enterprise Linux Eus
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel E4s
 
Red Hat Rhel Eus
 
Red Hat Hummingbird
 
Red Hat Rhui
 

Affected Versions

F5 NGINX Open Source: F5 NGINX Plus: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Extended Update Support: Red Hat Enterprise Linux 9.4 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Hardened Images: Red Hat Update Infrastructure 5: Red Hat Update Infrastructure 5:

Exploit Probability

EPSS
0.47%
Percentile
36.97%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.