CVE-2026-90439
MEDIUMDescription
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module. When using HTTP/3 with OpenSSL versions <= OpenSSL 3.5.0 under certain configurations, a limited heap buffer overflow could happen while processing a TLS handshake. This can happen in a non-deterministic manner that is beyond the attacker's control. This may cause a heap buffer overflow in the NGINX worker process leading to a restart and/or limited data corruption. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or limited data corruption. There is no control plane exposure; this is a data plane issue only. 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:U/C:N/I:L/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 17% of all known CVEs.
References
Related Vulnerabilities
Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2015-3113 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2020-25687 | Medium | 5.9 | 87% | - | Fix |
| CVE-2009-3459 | High | 8.8 | 87% | KEV | Fix |
| CVE-2021-21017 | High | 8.8 | 86% | KEV | - |
| CVE-2020-25683 | Medium | 5.9 | 86% | - | Fix |
| CVE-2023-27997 | Critical | 9.8 | 86% | KEV + Ransom | - |
Common questions
How do I fix CVE-2026-90439?
Upgrade nginx on debian unstable to 1.30.4-7 or later.
Is CVE-2026-90439 being actively exploited?
Not that we know of. CVE-2026-90439 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.26% is the estimated probability that it will be exploited in the next 30 days. That is higher than 17% of all scored CVEs.
How severe is CVE-2026-90439?
CVE-2026-90439 has a CVSS v3 base score of 6.5, 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-2026-90439 affect?
Published advisories record a fix for nginx (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-90439
Markdown
[](https://tridentstack.com/cve/CVE-2026-90439)HTML
<a href="https://tridentstack.com/cve/CVE-2026-90439"><img src="https://tridentstack.com/cve/badge/CVE-2026-90439.svg" alt="CVE-2026-90439"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
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 2026-09-18.