CVE-2026-119195：pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, construc
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, constructed string and indefinite-length ANY decoding repeatedly concatenates each fragment onto a growing bytes value. Attacker-controlled BER or CER data can use many constructed OCTET STRING or character-string fragments. DER rejects constructed OCTET STRING without a schema, but accepts its definite-length form when asn1Spec selects univ.OctetString; it also accepts constructed character strings such as UTF8String without a schema, even though those encodings are not valid DER. The separate indefinite-length ANY path is reachable in BER and CER when asn1Spec selects univ.Any; DER rejects indefinite lengths. OctetStringPayloadDecoder uses growing header concatenation and AnyPayloadDecoder.indefLenValueDecoder uses growing chunk concatenation, repeatedly copying an increasing prefix and causing quadratic work. A sufficiently fragmented value can occupy decoding workers and cause CPU exhaustion without confidentiality or integrity impact. This issue is fixed in version 0.6.5.
漏洞详情
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, constructed string and indefinite-length ANY decoding repeatedly concatenates each fragment onto a growing bytes value. Attacker-controlled BER or CER data can use many constructed OCTET STRING or character-string fragments. DER rejects constructed OCTET STRING without a schema, but accepts its definite-length form when asn1Spec selects univ.OctetString; it also accepts constructed character strings such as UTF8String without a schema, even though those encodings are not valid DER. The separate indefinite-length ANY path is reachable in BER and CER when asn1Spec selects univ.Any; DER rejects indefinite lengths. OctetStringPayloadDecoder uses growing header concatenation and AnyPayloadDecoder.indefLenValueDecoder uses growing chunk concatenation, repeatedly copying an increasing prefix and causing quadratic work. A sufficiently fragmented value can occupy decoding workers and cause CPU exhaustion without confidentiality or integrity impact. This issue is fixed in version 0.6.5.
风险评估
- CVSS 评分：7.5（HIGH）
- 评分版本：CVSS 3.1
- 攻击向量：
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
弱点类型
CWE-407
参考链接
- https://github.com/pyasn1/pyasn1/commit/4ce00797c594b59c1fd6b86d9ebc3ba87b7ec9f9
- https://github.com/pyasn1/pyasn1/pull/132
- https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5
- https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39
数据来源：NVD（美国国家漏洞数据库），入库时按 CVSS 评分筛选。
原文链接： CVE-2026-119195：pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, construc