{"schema_version":"1.7.5","id":"PYSEC-2026-2263","published":"2026-03-18T04:17:18.397Z","modified":"2026-07-13T07:15:40.277367904Z","aliases":["CVE-2026-30922","GHSA-jr27-m4p2-rc6r"],"details":"pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.3, the `pyasn1` library is vulnerable to a Denial of Service (DoS) attack caused by uncontrolled recursion when decoding ASN.1 data with deeply nested structures. An attacker can supply a crafted payload containing thousands of nested `SEQUENCE` (`0x30`) or `SET` (`0x31`) tags with \"Indefinite Length\" (`0x80`) markers. This forces the decoder to recursively call itself until the Python interpreter crashes with a `RecursionError` or consumes all available memory (OOM), crashing the host application. This is a distinct vulnerability from CVE-2026-23490 (which addressed integer overflows in OID decoding). The fix for CVE-2026-23490 (`MAX_OID_ARC_CONTINUATION_OCTETS`) does not mitigate this recursion issue. Version 0.6.3 fixes this specific issue.","affected":[{"package":{"name":"pyasn1","ecosystem":"PyPI","purl":"pkg:pypi/pyasn1"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.6.3"}]}],"versions":["0.0.10a","0.0.11a","0.0.12a","0.0.13","0.0.13a","0.0.13b","0.0.6a","0.0.9a","0.1.1","0.1.2","0.1.3","0.1.4","0.1.5","0.1.6","0.1.7","0.1.8","0.1.9","0.2.1","0.2.2","0.2.3","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.7","0.4.8","0.5.0","0.5.1","0.6.0","0.6.1","0.6.2"],"ecosystem_specific":{},"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pyasn1/PYSEC-2026-2263.yaml"}}],"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/03/20/4"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2026/05/msg00001.html"},{"type":"FIX","url":"https://github.com/pyasn1/pyasn1/commit/25ad481c19fdb006e20485ef3fc2e5b3eff30ef0"},{"type":"EVIDENCE","url":"https://github.com/pyasn1/pyasn1/security/advisories/GHSA-jr27-m4p2-rc6r"}],"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}