CVE-2026-42945
As of 2026-05-21, CVE-2026-42945 is a CVSS 8.1 (HIGH-severity) vulnerability. EPSS exploitation probability 0.9%. Threadlinqs Intelligence tracks 2 threats exploiting it.
Last updated: 2026-05-21
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewrite directive is followed by a rewrite, if, or set directive and an unnamed Perl-Compatible Regular Expression (PCRE) capture (for example, $1, $2) with a replacement string that includes a question mark (?). An unauthenticated attacker along with conditions beyond its control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap 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 v3 vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
CWE-122
Threats tracking this CVE
- F5 Patches Multiple NGINX Vulnerabilities: Heap Overflow, Memory Disclosure, and Use-After-Free (CVE-2026-42533, CVE-2026-60005, CVE-2026-56434) — CRITICAL
- NGINX Rift — CVE-2026-42945 Heap Buffer Overflow in ngx_http_rewrite_module (CVSS v4 9.2 Critical, 18-Year-Old Pre-Auth RCE, Public PoC) — CRITICAL
References
← all vulnerabilities · Markdown version · Threadlinqs Intelligence
Enriched from CVE.org, NVD (this product uses the NVD API but is not endorsed or certified by the NVD), FIRST EPSS, CISA KEV, and GitHub Security Advisories.