CVE-2026-27654
HighCVSS 8.2Exploitation Probability (EPSS)
Very high risk97th percentile - higher than 97% of all known CVEs
Summary
A vulnerability in the NGINX ngx_http_dav_module allows an attacker to trigger a buffer overflow in the NGINX worker process. The issue occurs when the configuration uses MOVE or COPY methods with alias directives and prefix locations.
Risk Assessment
The attack may cause termination of the NGINX worker process or modification of file names outside the document root, leading to data integrity issues. Risk is limited due to the low privileges of the worker process.
Recommendation
Immediately update NGINX to a patched version. If not possible, temporarily avoid using MOVE and COPY methods with alias directives in the configuration.
Other vulnerabilities in NGINX
See all- CVE-2016-1247High
The nginx package before 1.6.2-5+deb8u3 on Debian jessie and earlier versions on Ubuntu and Gentoo allow local users with access to the web server user account to gain root privileges via a symlink attack on the error log.
- CVE-2016-4450High
In nginx before 1.10.1 and 1.11.x before 1.11.1, a vulnerability allows remote attackers to cause a denial of service (NULL pointer dereference and worker process crash) via a crafted request, involving writing a client request body to a temporary file.
- CVE-2016-0742High
The resolver in nginx before 1.8.1 and 1.9.x before 1.9.10 allows remote attackers to cause a denial of service via an invalid pointer dereference, leading to a worker process crash.
- CVE-2014-0133High
Heap-based buffer overflow in the SPDY implementation in nginx 1.3.15 before 1.4.7 and 1.5.x before 1.5.12 allows remote attackers to execute arbitrary code via a crafted request.
- CVE-2026-42055High
Heap-based buffer overflow in NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module. Specific configuration conditions and large headers can cause NGINX worker process crash, and in some cases allow code execution.
- CVE-2026-9256High
A vulnerability in the ngx_http_rewrite_module of NGINX Plus and NGINX Open Source occurs when a rewrite directive uses a regex pattern with overlapping PCRE captures and a replacement string referencing multiple captures. An unauthenticated attacker can send crafted HTTP requests, causing a heap buffer overflow in the NGINX worker process, leading to a restart.
- CVE-2026-42945High
A vulnerability exists in NGINX Plus and NGINX Open Source within the ngx_http_rewrite_module. It occurs when the rewrite directive is followed by rewrite, if, or set directives and an unnamed PCRE capture (e.g., $1, $2) with a replacement string containing a question mark (?). An unauthenticated attacker can send crafted HTTP requests, causing a heap buffer overflow in the NGINX worker process, leading to a restart.
- CVE-2016-0746Critical
A use-after-free vulnerability in the resolver in nginx versions 0.6.18 through 1.8.0 and 1.9.x before 1.9.10 allows remote attackers to cause a denial of service (worker process crash) or possibly have unspecified other impact via a crafted DNS response related to CNAME response processing.
- CVE-2026-90439Medium
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module. When using HTTP/3 with OpenSSL versions <= OpenSSL 3.5.0 under certain configurations, a limited heap buffer overflow could happen while processing a TLS handshake. This can happen in a non-deterministic manner that is beyond the attacker's control. This may cause a heap buffer overflow in the NGINX worker process leading to a restart and/or limited data corruption.
- CVE-2026-60005High
A vulnerability exists in NGINX Plus and NGINX Open Source within the ngx_http_slice_module module. When the slice directive with unnamed regex captures is configured or during a background cache update, unauthenticated attackers can send requests causing uninitialized memory access in the NGINX worker process, leading to limited memory disclosure or a restart.
Original NVD description (English source)
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.