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Ubuntu Security NoticesUSN-8563-3

USN-8563-3: nginx vulnerability

Severity not listed 3 CVEs Published Aug 19, 2026 at 12:01 PM UTC

Summary

USN-8563-1 fixed vulnerabilities in nginx. The fix for CVE-2026-42533 was backed out in USN-8563-2 because it could cause a regression. This update includes a better fix for CVE-2026-42533. We apologize for the inconvenience. Original advisory details: It was discovered that nginx incorrectly handled certain map directives using regex matching and capture variables.

A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-42533)

It was discovered that nginx had a use-after-free vulnerability in the ngx_http_ssi_module module when configured with Server-Side Includes, proxy_pass, and proxy buffering disabled directives. An attacker able to intercept traffic and control responses from an upstream server could possibly use this issue to cause nginx to crash, resulting in a denial of service. (CVE-2026-56434)

It was discovered that nginx incorrectly handled certain requests in the ngx_http_slice_module module. A remote attacker could possibly use this issue to obtain sensitive information or cause nginx to crash, resulting in a denial of service. (CVE-2026-60005)

Products covered

A separate affected-products list was not included in the collected bulletin.

Remediation

USN-8563-1 fixed vulnerabilities in nginx.

CVEs in this advisory 3

Updates

  1. Published by Ubuntu

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.