# CVE-2026-42926

## Summary

- **CVE ID:** CVE-2026-42926
- **Severity:** MEDIUM
- **CVSS Score:** 6.3 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N)
- **CWE:** CWE-172
- **Published:** May 13, 2026
- **Last Modified:** May 13, 2026

## Description

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.

## Affected Products

- F5 — NGINX Open Source (1.31.0)
- F5 — NGINX Open Source (1.29.4)

## References

- [CNA](https://my.f5.com/manage/s/article/K000161131)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.35%
- **EPSS Percentile:** 27.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._