CVE-2026-119196：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 BIT STRING decoding repeatedly shifts and copies the complete bit value accumulated from earlier fragments. Attacker-controlled BER or CER input contains many constructed BIT STRING fragments; schema-driven DER also accepts a definite-length constructed BIT STRING. BitStringPayloadDecoder repeatedly calls BitString.fromOctetString with the prior bitString as prepend, shifting an ever-growing SizedInteger for each fragment and causing quadratic work. Large fragmented values can exhaust CPU during decode() without requiring later conversion or formatting. 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 BIT STRING decoding repeatedly shifts and copies the complete bit value accumulated from earlier fragments. Attacker-controlled BER or CER input contains many constructed BIT STRING fragments; schema-driven DER also accepts a definite-length constructed BIT STRING. BitStringPayloadDecoder repeatedly calls BitString.fromOctetString with the prior bitString as prepend, shifting an ever-growing SizedInteger for each fragment and causing quadratic work. Large fragmented values can exhaust CPU during decode() without requiring later conversion or formatting. 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/73ba7b043cc7e92cb37f16f2c955bff93b0e6f6c
- 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-2qm8-x737-gmw5
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-2026-119196：pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, construc