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NGINX: Man-in-the-middle attackers can inject plain text into responses

OESA-2026-1572
Summary

NGINX users who proxy TLS traffic to other servers may be at risk of having sensitive data tampered with. This could lead to data integrity issues. To protect your systems, update to the latest version of NGINX.

What to do
  • Update nginx to version 1.21.5-9.oe2003sp4.
  • Update nginx to version 1.21.5-11.oe2203sp4.
  • Update nginx to version 1.24.0-7.oe2403sp3.
  • Update nginx to version 1.24.0-7.oe2403sp1.
  • Update nginx to version 1.24.0-7.oe2403sp2.
Affected software
VendorProductAffected versionsFix available
nginx <= 1.21.5-9.oe2003sp4 1.21.5-9.oe2003sp4
nginx <= 1.21.5-11.oe2203sp4 1.21.5-11.oe2203sp4
nginx <= 1.24.0-7.oe2403sp3 1.24.0-7.oe2403sp3
nginx <= 1.24.0-7.oe2403sp1 1.24.0-7.oe2403sp1
nginx <= 1.24.0-7.oe2403sp2 1.24.0-7.oe2403sp2
nginx <= 1.24.0-7.oe2403sp3 1.24.0-7.oe2403sp3
Original title
nginx security update
Original description
NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server.

Security Fix(es):

A vulnerability exists in NGINX OSS and NGINX Plus when configured to proxy to upstream Transport Layer Security (TLS) servers. An attacker with a man-in-the-middle (MITM) position on the upstream server side—along with conditions beyond the attacker&apos;s control—may be able to inject plain text data into the response from an upstream proxied server. The vulnerability is classified as CWE-349: The product, when processing trusted data, accepts any untrusted data that is also included with the trusted data, treating the untrusted data as if it were trusted. This vulnerability primarily affects data integrity.(CVE-2026-1642)
Published: 15 Mar 2026 · Updated: 15 Mar 2026 · First seen: 15 Mar 2026