{"id":"GHSA-r8wq-qrxc-hmcm","summary":"ReDoS in LDAP schema parser","details":"https://github.com/python-ldap/python-ldap/issues/424\n\n### Impact\nThe LDAP schema parser of python-ldap 3.3.1 and earlier are vulnerable to a regular expression denial-of-service attack. The issue affects clients that use ``ldap.schema`` package to parse LDAP schema definitions from an untrusted source.\n\n### Patches\nThe upcoming release of python-ldap 3.4.0 will contain a workaround to prevent ReDoS attacks. The schema parser refuses schema definitions with an excessive amount of backslashes.\n\n### Workarounds\nAs a workaround, users can check input for excessive amount of backslashes in schemas. More than a dozen backslashes per line are atypical.\n\n### References\n[CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [python-ldap](https://github.com/python-ldap/python-ldap) tracker\n","aliases":["CVE-2021-46823","GHSA-qfr5-wjpw-q4c4","PYSEC-2026-912"],"modified":"2026-07-07T11:56:47.867526388Z","published":"2021-11-29T17:58:59Z","database_specific":{"github_reviewed_at":"2021-11-26T18:26:27Z","nvd_published_at":null,"cwe_ids":["CWE-1333"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/python-ldap/python-ldap/security/advisories/GHSA-r8wq-qrxc-hmcm"},{"type":"WEB","url":"https://github.com/python-ldap/python-ldap/issues/424"},{"type":"PACKAGE","url":"https://github.com/python-ldap/python-ldap"}],"affected":[{"package":{"name":"python-ldap","ecosystem":"PyPI","purl":"pkg:pypi/python-ldap"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.0"}]}],"versions":["2.3.13","2.4.0","2.4.1","2.4.10","2.4.12","2.4.13","2.4.14","2.4.15","2.4.16","2.4.17","2.4.18","2.4.19","2.4.2","2.4.20","2.4.21","2.4.22","2.4.25","2.4.26","2.4.27","2.4.28","2.4.29","2.4.3","2.4.30","2.4.31","2.4.32","2.4.33","2.4.35","2.4.36","2.4.37","2.4.38","2.4.39","2.4.4","2.4.40","2.4.41","2.4.42","2.4.43","2.4.44","2.4.45","2.4.5","2.4.6","2.4.7","2.4.8","2.4.9","2.5.1","2.5.2","3.0.0","3.0.0b1","3.0.0b2","3.0.0b3","3.0.0b4","3.1.0","3.2.0","3.3.0","3.3.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/11/GHSA-r8wq-qrxc-hmcm/GHSA-r8wq-qrxc-hmcm.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}