NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability
48Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 9.2epss 4.0%
from disclosure to weapon2 days
Published on NVDJun 17
1st PoC+2d
exploitation probability
4.0%top 10% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
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.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
public PoCs found — 1
githubgithub.com/HORKimhab/CVE-2026-42055★ 0⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://access.redhat.com/errata/RHSA-2026:27197https://access.redhat.com/errata/RHSA-2026:36331https://access.redhat.com/errata/RHSA-2026:36364https://access.redhat.com/errata/RHSA-2026:36618https://access.redhat.com/errata/RHSA-2026:36639https://access.redhat.com/errata/RHSA-2026:38847https://access.redhat.com/errata/RHSA-2026:44481https://access.redhat.com/errata/RHSA-2026:46836https://access.redhat.com/security/cve/CVE-2026-42055https://bugzilla.redhat.com/show_bug.cgi?id=2489866https://my.f5.com/manage/s/article/K000161584https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42055.json