Description: NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
The CVSS Base Score is a score from 0 to 10 that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.
Database CWE: v4.18
CWE-122: 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().
CWE-787: Out-of-bounds Write ↗
The product writes data past the end, or before the beginning, of the intended buffer.
CWE-131: Incorrect Calculation of Buffer Size ↗
The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.
Fonte: MITRE CWE
The EPSS (Exploit Prediction Scoring System) is a score from 0 to 1 that indicates the probability that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.
The Percentile indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.
*Data updated as of: 2026-08-13
The CISA KEV Catalog lists vulnerabilities that have been actively exploited in the real world. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.
CVE CVE-2026-42055 is not present in the CISA KEV Catalog. This indicates that it is not currently classified by CISA as an actively exploited vulnerability.