Vulnerability details
CVE-2026-42530
F5 NGINX Open Source
NGINX Open-Source ngx_http_v3_module vulnerability
CVSS 4.0
9.2Critical
Official description
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 scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.2Critical | 4.0 | CVEProject cvelistV5 (CNA) (f5) | 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 |
| 8.1High | 3.1 | CVEProject cvelistV5 (CNA) (f5) | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 8.1High | 3.1 | CVEProject cvelistV5 (CNA) (redhat-SADP) | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| F5 | NGINX Open Source | 1.31.0 ≤ v < 1.31.2 | CVEProject cvelistV5 (CNA) |
References and advisories
5- https://my.f5.com/manage/s/article/K000161616 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-42530 vdb-entryx_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2489872 issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42530.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:20351 vendor-advisoryx_refsource_REDHAT
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Details
- Published
- 2026-06-17
- Last updated
- 2026-07-16
- State
- Published
- Assigner (CNA)
- f5
Exploit prediction (EPSS)
6.21%
Probability of exploitation in 30 days
93.5%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-416Use After Free