- Description
- 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.
- Source
- security-advisories@github.com
- NVD status
- Modified
- Products
- pyasn1
CVSS 3.1
- Type
- Secondary
- Base score
- 7.5
- Impact score
- 3.6
- Exploitability score
- 3.9
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Severity
- HIGH
- Hype score
- Not currently trending
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{
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{
"cpeMatch": [
{
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"matchCriteriaId": "3F5F876E-E9B5-45D9-AE85-5E3E35AD09D7",
"versionEndExcluding": "0.6.3",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
]