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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Pyasn1 | Pyasn1 | < 0.6.4 |
Related Weaknesses (CWE)
References
- https://github.com/pyasn1/pyasn1/commit/e60c691cb91addb8fcefa2f537e85ede6fb1e886Patch
- https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4Release Notes
- https://github.com/pyasn1/pyasn1/security/advisories/GHSA-hm4w-wwcw-mr6rThird Party Advisory
FAQ
What is CVE-2026-59886?
CVE-2026-59886 is a vulnerability with a CVSS score of 7.5 (HIGH). 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, ...
How severe is CVE-2026-59886?
CVE-2026-59886 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59886?
Check the references section above for vendor advisories and patch information. Affected products include: Pyasn1 Pyasn1.