CVE-2026-42530: critical vulnerability in F5 NGINX Open Source
NGINX Open-Source ngx_http_v3_module vulnerability
Published · Updated
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48Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 9.2epss 6.2%
from disclosure to weapon2 days
Published on NVDJun 17
1st PoC+2d
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:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
F5 · NGINX Open Sourcepublic PoCs found — 3
githubgithub.com/v4ltonn/CVE-2026-42530★ 4githubgithub.com/0xBlackash/CVE-2026-42530★ 3githubgithub.com/HORKimhab/CVE-2026-42530★ 0⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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