Bug 2501248

Summary: CVE-2026-59886 python-pyasn1: pyasn1: Denial of Service via crafted ASN.1 REAL values [fedora-all]
Product: [Fedora] Fedora Reporter: Jeremy Choi <jechoi>
Component: python-pyasn1Assignee: Rob Crittenden <rcritten>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: 45CC: rcritten, spichugi
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["2093750a-1526-4320-bd42-8e06f178d903"]}
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Doc Text:
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Last Closed: 2026-10-30 23:53:09 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2500041    

Description Jeremy Choi 2026-07-16 03:29:26 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.
Comment 1 Aoife Moloney 2026-08-17 15:20:46 UTC 
This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.
Comment 2 Simon Pichugin 2026-10-30 23:53:09 UTC 
It's fixed in all supported Fedora releases.