Quick answers
- Is CVE-2026-90439 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-90439 being exploited in the wild.
- How severe is CVE-2026-90439?
- Medium severity, with a CVSS score of 6.5, published 15 September 2026.
- Which products and versions are affected?
- NGINX Open Source versions using ngx_http_v3_module with OpenSSL <= 3.5.0; OpenSSL <= 3.5.0.
- Is there a fix for CVE-2026-90439?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-90439 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-90439?
- Check whether you run NGINX Open Source or OpenSSL at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
This vulnerability is a heap buffer overflow in the ngx_http_v3_module module that occurs during TLS handshake processing in HTTP/3 connections when OpenSSL versions <= 3.5.0 are used under specific configurations. The overflow is non-deterministic and beyond an attacker's direct control. A remote attacker can exploit this without authentication by sending a specially crafted TLS handshake packet, leading to a worker process restart and/or limited data corruption. The vulnerability is data-plane only with no control-plane exposure. Patches should be available from NGINX; affected versions should be reviewed against official security advisories.
Affected products
- NGINX NGINX Plus versions using ngx_http_v3_module with OpenSSL <= 3.5.0
- NGINX NGINX Open Source versions using ngx_http_v3_module with OpenSSL <= 3.5.0
- OpenSSL OpenSSL <= 3.5.0
Timeline
- 2026-09-15: disclosed: Vulnerability published