USN-7927-2: urllib3 regression

USN-7927-2: urllib3 regression

https://ubuntu.com/security/notices/rss.xml / Tue, 01/13/2026 - 01:57
USN-7927-1 fixed vulnerabilities in urllib3. The update for CVE-2025-66471 introduced a regression in the zstd decompression component inside urllib3. This update fixes the problem. We apologize for the inconvenience. Original advisory details: Illia Volochii discovered that urllib3 did not limit the steps in a decompression chain. An attacker could possibly use this issue to cause urllib3 to use excessive resources, causing a denial of service. (CVE-2025-66418) Rui Xi discovered that urllib3 incorrectly handled highly compressed data. An attacker could possibly use this issue to cause urllib3 to use excessive resources, causing a denial of service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.04, and Ubuntu 25.10. (CVE-2025-66471) For the brotli encoding, the fix for CVE-2025-66471 requires an additional security update in the brotli package.

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