CVE-2025-61920 SUSE CVE security@suse.de SUSE Security Team SUSE CVE-2025-61920 Interim 1 2 2025-12-23T00:16:17Z current 2025-11-01T00:15:05Z 2025-12-23T00:16:17Z cve-database/bin/generate-cvrf-cve.pl 2020-12-27T01:00:00Z CVE-2025-61920 Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib's JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url-encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk. The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). https://lists.suse.com/pipermail/sle-security-updates/2025-October/022984.html E-Mail link for SUSE-SU-2025:3754-1 https://www.suse.com/support/security/rating/ SUSE Security Ratings SUSE Linux Enterprise Module for Python 3 15 SP6 SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Module for Python 3 15 SP6 SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Module for Python 3 15 SP6 SUSE Linux Enterprise Module for Python 3 15 SP7 SUSE Linux Enterprise Module for Python 3 15 SP6 SUSE Linux Enterprise Module for Python 3 15 SP7 openSUSE Leap 15.6 openSUSE Tumbleweed python311-Authlib-1.3.1-150600.3.6.1 python311-Authlib-1.6.5-1.1 python312-Authlib-1.6.5-1.1 python313-Authlib-1.6.5-1.1 python311-Authlib-1.3.1-150600.3.6.1 as a component of SUSE Linux Enterprise Module for Python 3 15 SP6 python311-Authlib-1.3.1-150600.3.6.1 as a component of SUSE Linux Enterprise Module for Python 3 15 SP7 python311-Authlib-1.3.1-150600.3.6.1 as a component of openSUSE Leap 15.6 python311-Authlib-1.6.5-1.1 as a component of openSUSE Tumbleweed python312-Authlib-1.6.5-1.1 as a component of openSUSE Tumbleweed python313-Authlib-1.6.5-1.1 as a component of openSUSE Tumbleweed Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib's JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url-encoded header or signature spans hundreds of megabytes. During verification, Authlib decodes and parses the full input before it is rejected, driving CPU and memory consumption to hostile levels and enabling denial of service. Version 1.6.5 patches the issue. Some temporary workarounds are available. Enforce input size limits before handing tokens to Authlib and/or use application-level throttling to reduce amplification risk. CVE-2025-61920 SUSE Linux Enterprise Module for Python 3 15 SP6:python311-Authlib-1.3.1-150600.3.6.1 SUSE Linux Enterprise Module for Python 3 15 SP7:python311-Authlib-1.3.1-150600.3.6.1 openSUSE Leap 15.6:python311-Authlib-1.3.1-150600.3.6.1 openSUSE Tumbleweed:python311-Authlib-1.6.5-1.1 openSUSE Tumbleweed:python312-Authlib-1.6.5-1.1 openSUSE Tumbleweed:python313-Authlib-1.6.5-1.1 important 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H