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CVE-2026-59886— pyasn1: Uncontrolled resource consumption when converting decoded REAL values

Quick assessment

Affected
pyasn1 pyasn1
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

pyasn1是pyasn1组织开源的一个PythonASN.1库。 pyasn1 0.6.4之前版本存在资源管理错误漏洞，该漏洞源于univ.Real类型使用精确大整数幂运算转换其尾数、基数和指数值为Python浮点数，可能导致通过prettyPrint()、str()、比较、算术、int()或显式float()调用进行浮点转换时消耗过多CPU和内存，并挂起解码不可信ASN.1数据然后打印、记录或比较解码结果的应用。

CVSS 7.5 · High EPSS 0.34% · P27

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
pyasn1 pyasn1 < 0.6.4 affected
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I. Basic Information for CVE-2026-59886

Vulnerability Information
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Vulnerability Title
pyasn1: Uncontrolled resource consumption when converting decoded REAL values
Source: CVE Program / CVE List V5
Vulnerability Description
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa, base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded objects. This issue is fixed in version 0.6.4.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
pyasn1 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
pyasn1是pyasn1组织开源的一个PythonASN.1库。 pyasn1 0.6.4之前版本存在资源管理错误漏洞，该漏洞源于univ.Real类型使用精确大整数幂运算转换其尾数、基数和指数值为Python浮点数，可能导致通过prettyPrint()、str()、比较、算术、int()或显式float()调用进行浮点转换时消耗过多CPU和内存，并挂起解码不可信ASN.1数据然后打印、记录或比较解码结果的应用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
pyasn1 pyasn1 < 0.6.4 -

II. Public POCs for CVE-2026-59886

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8288 chars
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III. Intelligence Information for CVE-2026-59886

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Patches & Fixes for CVE-2026-59886 (1)

Vendor Advisories for CVE-2026-59886 (1)

Vendor Pages for CVE-2026-59886 (1)

Same Patch Batch · pyasn1 · 2026-07-14 · 3 CVEs total

CVE-2026-59884 7.5 HIGH pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs
CVE-2026-59885 7.5 HIGH pyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denia

IV. Related Vulnerabilities

Same product: pyasn1
Same vendor: pyasn1
Same weakness: CWE-400

V. Comments for CVE-2026-59886

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