Bug 2491878 (CVE-2026-57053)

Summary: CVE-2026-57053 libidn: GNU libidn: Out-of-bounds read in ToUnicode APIs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dymurray, ibolton, jmatthew, jmontleo, pgaikwad, rhel-process-autobot, rjohnson, slucidi, sseago, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in GNU libidn. This vulnerability allows an attacker to cause out-of-bounds reads of uninitialized memory within the ToUnicode APIs due to mishandling in the `idna_to_unicode_internal` function. This could lead to information disclosure or a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2509780, 2509778, 2509779, 2509781    
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Description OSIDB Bzimport 2026-06-23 18:02:35 UTC
GNU libidn before 1.44 is prone to out-of-bounds reads of uninitialized memory in the ToUnicode APIs because of mishandling in idna_to_unicode_internal. The affected code is not present in libidn2.