Bug 2500656 (CVE-2026-48801)

Summary: CVE-2026-48801 linkify-it: linkify-it: Denial of Service via algorithmic complexity vulnerability
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: abarbaro, alizardo, cdrage, dkeler, dschmidt, jchui, jhe, jlanda, kbempah, kshier, ktsao, manissin, nboldt, oaljalju, psrna, rushinde, sdawley, simaishi, solenoci, stcannon, suppawar, teagle, thason, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in linkify-it, a library for recognizing links with full Unicode support. The LinkifyIt.prototype.match function, the package's primary public API, has an algorithmic complexity of O(N²) for inputs containing many fuzzy links or emails. This can be exploited by a remote attacker sending a specially crafted request body, leading to a worker-process denial of service (DoS) due to excessive CPU usage when synchronously rendering untrusted Markdown with linkify enabled.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2500946, 2500947, 2500948, 2500949, 2500945, 2500950, 2500951    
Bug Blocks:    

Description OSIDB Bzimport 2026-07-14 21:03:18 UTC 
linkify-it is a links recognition library with full Unicode support. Prior to 5.0.1, LinkifyIt.prototype.match, the package's primary public API, has O(N²) algorithmic complexity for inputs containing many fuzzy links or emails because the JavaScript-level scan loop re-slices input and re-runs unanchored regex searches on progressively shorter tails. Any service that synchronously renders untrusted Markdown with linkify:true on a request hot path can inherit a worker-process denial of service triggerable by a tens-of-KB request body. This issue is fixed in version 5.0.1.
Comment 6 errata-xmlrpc 2026-08-20 16:07:29 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:57590 https://access.redhat.com/errata/RHSA-2026:57590