Vulnerability Details CVE-2026-30922
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 7.1%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-30922
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cpe:2.3:a:pyasn1:pyasn1:0.2.1
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cpe:2.3:a:pyasn1:pyasn1:0.2.2
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cpe:2.3:a:pyasn1:pyasn1:0.2.3
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cpe:2.3:a:pyasn1:pyasn1:0.3.1
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cpe:2.3:a:pyasn1:pyasn1:0.3.2
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cpe:2.3:a:pyasn1:pyasn1:0.3.3
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cpe:2.3:a:pyasn1:pyasn1:0.3.4
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cpe:2.3:a:pyasn1:pyasn1:0.3.5
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cpe:2.3:a:pyasn1:pyasn1:0.3.6
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cpe:2.3:a:pyasn1:pyasn1:0.3.7
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cpe:2.3:a:pyasn1:pyasn1:0.4.1
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cpe:2.3:a:pyasn1:pyasn1:0.4.2
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cpe:2.3:a:pyasn1:pyasn1:0.4.3
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cpe:2.3:a:pyasn1:pyasn1:0.4.4
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cpe:2.3:a:pyasn1:pyasn1:0.4.5
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cpe:2.3:a:pyasn1:pyasn1:0.4.6
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cpe:2.3:a:pyasn1:pyasn1:0.4.7
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cpe:2.3:a:pyasn1:pyasn1:0.4.8
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cpe:2.3:a:pyasn1:pyasn1:0.5.0
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cpe:2.3:a:pyasn1:pyasn1:0.5.1
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cpe:2.3:a:pyasn1:pyasn1:0.6.0
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cpe:2.3:a:pyasn1:pyasn1:0.6.1
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cpe:2.3:a:pyasn1:pyasn1:0.6.2