{"id":"CVE-2026-3446","summary":"Base64 decoding stops at first padded quad by default","details":"When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use \"validate=True\" to enable stricter processing of base64 data.","aliases":["BIT-libpython-2026-3446","BIT-python-2026-3446","BIT-python-min-2026-3446","PSF-2026-16"],"modified":"2026-06-20T18:29:21.591772411Z","published":"2026-04-10T18:17:35.045Z","related":["SUSE-SU-2026:1502-1","SUSE-SU-2026:1503-1","SUSE-SU-2026:1715-1","SUSE-SU-2026:1818-1","SUSE-SU-2026:1937-1","SUSE-SU-2026:1947-1","SUSE-SU-2026:21415-1","SUSE-SU-2026:21447-1","SUSE-SU-2026:2298-1","SUSE-SU-2026:2464-1","openSUSE-SU-2026:10579-1","openSUSE-SU-2026:10580-1","openSUSE-SU-2026:10667-1","openSUSE-SU-2026:11068-1"],"database_specific":{"cna_assigner":"PSF","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3446.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3446.json"},{"type":"ADVISORY","url":"https://mail.python.org/archives/list/security-announce@python.org/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3446"},{"type":"REPORT","url":"https://github.com/python/cpython/issues/145264"},{"type":"FIX","url":"https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474"},{"type":"FIX","url":"https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e"},{"type":"FIX","url":"https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa"},{"type":"FIX","url":"https://github.com/python/cpython/pull/145267"},{"type":"PACKAGE","url":"https://github.com/python/cpython"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"introduced":"ebf955df7a89ed0c7968f79faec1de49f61ed7cb"},{"introduced":"f31a89bb901067dd105b00cfa90523cf7ffdbbdd"},{"fixed":"01104ce1beb3135c2e0c01ec835b994c1f55a1c0"},{"fixed":"23116f998f6789d8c2fbe5ed5b8146854c8c2a4f"},{"fixed":"55ea59e7dc35e1363b203ae4dd9cfc3a0ac0a844"},{"fixed":"1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474"},{"fixed":"4561f6418a691b3e89aef0901f53fe0dfb7f7c0e"},{"fixed":"e31c55121620189a0d1a07b689762d8ca9c1b7fa"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.13.13"},{"introduced":"3.14.0"},{"fixed":"3.14.4"},{"introduced":"3.15.0a1"},{"fixed":"3.15.0a8"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v3.15.0a7","v3.15.0a6","v3.13.12","v3.14.3","v3.15.0a5","v3.15.0a4","v3.15.0a3","v3.14.2","v3.13.11","v3.13.10","v3.14.1","v3.15.0a2","v3.15.0a1","v3.13.8","v3.14.0","v3.13.7","v3.13.6","v3.13.5","v3.13.4","v3.14.0b1","v3.13.3","v3.14.0a7","v3.14.0a6","v3.14.0a5","v3.13.2","v3.14.0a4","v3.14.0a3","v3.13.1","v3.14.0a2","v3.14.0a1","v3.13.0","v3.13.0rc3","v3.13.0rc2","v3.13.0rc1","v3.13.0b4","v3.13.0b3","v3.13.0b2","v3.13.0b1","v3.13.0a6","v3.13.0a5","v3.13.0a4","v3.13.0a3","v3.13.0a2","v3.13.0a1","v3.12.0b1","v3.12.0a7","v3.12.0a6","v3.12.0a5","v3.12.0a4","v3.12.0a3","v3.12.0a2","v3.12.0a1","v3.11.0b1","v3.11.0a7","v3.11.0a6","v3.11.0a5","v3.11.0a4","v3.11.0a3","v3.10.0a7","v3.10.0a1","v3.9.0a2","v3.7.0a2","v3.6.0b1","v3.6.0a3","v3.5.0b1","v3.5.0a4","v3.5.0a3","v3.5.0a2","v3.5.0a1","v3.4.0b3","v3.4.0b2","v3.4.0b1","v3.4.0a4","v3.4.0a3","v3.4.0a2","v3.4.0a1","v3.3.0rc3","v3.3.0rc2","v3.3.0rc1","v3.3.0b2","v3.3.0b1","v3.3.0a4","v3.3.0a3","v3.3.0a2","v3.2rc3","v3.2rc2","v3.2rc1","v3.2b2","v3.2b1","v3.2a4","v3.2a3","v3.2a2","v3.2a1","v3.1","v3.1rc2","v3.1rc1","v3.1b1","v3.1a2","v3.1a1","v3.0rc3","v3.0rc2","v3.0rc1","v3.0b3","v3.0b2","v3.0b1","v3.0a5","v3.0a4","v3.0a3","v3.0a2","v3.0a1","v2.4","v2.4c1","v2.4b2","v2.4b1","v2.4a3","v2.4a2","v2.4a1","v2.3c2","v2.3c1","v2.2a3","v2.1","v2.1c2","v2.1c1","v2.1b2","v2.1b1","v2.1a2","v2.1a1","v2.0","v2.0c1","v2.0b2","v2.0b1","v1.6a2","v1.6a1","v1.5.2","v1.5.2c1","v1.5.2b2","v1.5.2b1","v1.5.2a2","v1.5.2a1","v1.5.1","v1.5","v1.5b2","v1.5b1","v1.5a4","v1.5a3","v1.5a2","v1.5a1","v1.4","v1.4b3","v1.4b2","v1.4b1","v1.3","v1.3b1","v1.2","v1.2b4","v1.2b3","v1.2b2","v1.2b1","v1.1.1","v1.1","v1.0.2","v1.0.1","v0.9.9","v0.9.8"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-3446.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"}]}