CVE-2026-42926
MEDIUMDescription
When NGINX Open Source is configured to proxy HTTP/2 traffic by setting proxy_http_version to 2, and also uses proxy_set_body, an attacker may be able to inject frame headers and payload bytes to the upstream peer. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 28% of all known CVEs.
References
Related Vulnerabilities
Other CWE-172 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2019-10160 | Critical | 9.8 | 5.2% | - | Fix |
| CVE-2019-10153 | Medium | 5.0 | 2.2% | - | Fix |
| CVE-2018-7289 | Low | 3.3 | 1.7% | - | - |
| CVE-2019-12677 | Medium | 6.5 | 1.5% | - | Fix |
| CVE-2018-3777 | Critical | 9.8 | 1.5% | - | Fix |
| CVE-2016-6691 | Critical | 9.8 | 1.3% | - | - |
Common questions
How do I fix CVE-2026-42926?
Published advisories record a fix for 19 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2026-42926 being actively exploited?
Not that we know of. CVE-2026-42926 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.35% is the estimated probability that it will be exploited in the next 30 days. That is higher than 28% of all scored CVEs.
How severe is CVE-2026-42926?
CVE-2026-42926 has a CVSS v3 base score of 5.8, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-42926 affect?
Published advisories record a fix for nginx (Amazon), nginx-all-modules (Amazon), nginx-core (Amazon), nginx-core-debuginfo (Amazon), and 15 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-18.