High 7.5Published Jul 14, 2026

CVE-2026-59886pyasn1 is a generic ASN.1 library for Python.

Updated under an hour ago (2026-10-19 09:20 UTC)

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Every CVE for pyasn1

Exploited in the last 30 days

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: 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jul 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

pyasn1 pyasn1 pyasn1:pyasn1	before 0.6.4	NVD

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.