Vulnerability intelligence

CVE-2026-42530

NGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream. This may cause a Use-after-Free 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 Score

9.2

Critical

EPSS — Exploit Probability

3.7%

Riskier than 89% of all CVEs

Exploitation

Not in CISA KEV

No federal exploitation record

Remediation

Patch available

Vendor fix published