CVE-2026-27784: NGINX ngx_http_mp4_module vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-24 · updated 2026-07-15
Weakness: CWE-190

Description

The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the attack is possible only if an attacker can trigger the processing of a specially crafted MP4 file with the ngx_http_mp4_module module. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

F5 NGINX Open Source: from 1.1.19 before 1.28.3; from 1.29.0 before 1.29.7 — fixed in 1.28.3, 1.29.7

How to fix

Upgrade to a fixed version: F5 NGINX Open Source 1.28.3, 1.29.7. Check the vendor advisory for mitigations.

References

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