CVEvulnerability
CVE-2026-119197
Exploitation and prioritisation
- EPSS
- 0.43% chance of exploitation in the next 30 days · in the top 63.2% of all CVEs (2026-11-03)
- CISA SSVC: exploitation
- none
- CISA SSVC: automatable
- yes
- CISA SSVC: technical impact
- partial
- EU Vulnerability Database
- EUVD-2026-113353
Affected packages
| Ecosystem | Package | Vulnerable | Fixed in | Advisory |
|---|---|---|---|---|
| PyPI | pyasn1 | < 0.6.5 | 0.6.5 | GHSA-mm57-4v3p-rchx |
- Status
- Awaiting Analysis
- Published
- 2026-10-29
- Last modified
- 2026-10-30
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-407
Description
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, binary REAL decoding builds a large mantissa one octet at a time by shifting a growing integer and slicing the remaining byte string. Attacker-controlled ASN.1 includes a binary-encoded REAL with a large mantissa and reaches BER, CER, or DER decode(), with or without a schema containing REAL. RealPayloadDecoder.valueDecoder repeatedly performs a left shift, OR, and suffix copy for every mantissa octet, making decode time quadratic in mantissa length. A comparatively small REAL value can hold a decoding worker on one CPU core for seconds or longer and cause availability loss. This issue is fixed in version 0.6.5.
Related
Weakness · CWE (1)
- CWE-407 Inefficient Algorithmic Complexity weakness
Referenced by GitHub Advisory · alias (1)
- GHSA-mm57-4v3p-rchx pyasn1 has quadratic-complexity denial of service in binary REAL decoding advisory · PyPI