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
0.0%
Riskier than 0% of all CVEs
Exploitation
Not in CISA KEV
No federal exploitation record
Remediation
unknown
Check vendor advisories
1 article across 1 outlet · first covered Jun 18, 2026 · latest Jun 18, 2026
Coverage timeline
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F5 patches NGINX remote code flaws CVE-2026-42530, CVE-2026-42055www.securityweek.com · Jun 18, 2026