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HIGH

CVE-2026-59886

CVSS v3

7.5

HIGH

EPSS Score

0.6 %

exploit probability, as of 2026-10-17

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • pyasn1PyPIall versions · fixed in 0.6.4
  • fence-agents-apcAlmaLinux:8all versions · fixed in 4.2.1-129.el8_10.29and 47 other packages
  • fence-virtdAlmaLinux:9all versions · fixed in 4.10.0-110.el9_8.6and 55 other packages
  • python3-pyasn1AlmaLinux:10all versions · fixed in 0.6.2-1.el10_2.1and 1 other package
  • python3-pyasn1AlmaLinux:9all versions · fixed in 0.4.8-7.el9_8.1and 1 other package
  • python3-pyasn1AlmaLinux:8all versions · fixed in 0.3.7-6.el8_10.2and 1 other package
  • resource-agentsAlmaLinux:8all versions · fixed in 4.9.0-54.el8_10.37.alma.1and 3 other packages

Vendor advisories

  • CVE-2026-59886 Red Hat Product Security1,342 products fixed · 115 known affected

    pyasn1: pyasn1: Denial of Service via crafted ASN.1 REAL values

    exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · lightspeed-core/lightspeed-stack-rhel9 as a component of Lightspeed Core · mta/mta-solution-server-rhel9 as a component of Migration Toolkit for Applications 8

  • RHSA-2026:83121 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat AI Inference 3.4.6 (rocm)

  • RHSA-2026:81110 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay

  • RHSA-2026:77532 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Release of components for Service Telemetry Framework 1.5.7

  • RHSA-2026:74648 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: General availability of the satellite/iop-advisor-backend-rhel9 container image

  • RHSA-2026:73987 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: RHOAI 3.3.7 - Red Hat OpenShift AI

49 more advisories

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-07-14
Last Modified
2026-07-15
GitHub Advisory
GHSA-hm4w-wwcw-mr6r

Frequently asked questions

What is CVE-2026-59886?

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.

Is CVE-2026-59886 actively exploited?

Active exploitation of CVE-2026-59886 has not been confirmed. Its EPSS score was 0.6% on 2026-10-17, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-59886?

CVE-2026-59886 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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