Bug 2523477

Summary: CVE-2026-67214 jupyterlab: nanoid: Denial of Service via negative size input in non-secure module functions [fedora-all]
Product: [Fedora] Fedora Reporter: Joel Chamberlain <jochambe>
Component: jupyterlabAssignee: Lumír Balhar <lbalhar>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: lbalhar, python-packagers-sig, romain.geissler
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["f541dbf1-ce45-491a-9832-abc0354b81a5"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2508411    

Description Joel Chamberlain 2026-08-25 14:34:10 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.

nanoid (Nano ID) before 5.1.16 contains an infinite loop in the customAlphabet and nanoid functions of its non-secure module (nanoid/non-secure). When these functions are given a negative size, the loop counter is decremented from a negative value and never reaches its termination condition, spinning indefinitely and hanging the calling thread. An application that passes an unvalidated, attacker-controlled negative size to these functions is exposed to a denial-of-service condition.