Bug 2435940 (CVE-2026-1757)

Summary: CVE-2026-1757 libxml2: Memory Leak Leading to Local Denial of Service in xmllint Interactive Shell
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: adudiak, caswilli, crizzo, csutherl, gtanzill, jbuscemi, jclere, jmitchel, kaycoth, kshier, pbohmill, pjindal, plodge, stcannon, szappis, teagle, vchlup, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was identified in the interactive shell of the xmllint utility, part of the libxml2 project, where memory allocated for user input is not properly released under certain conditions. When a user submits input consisting only of whitespace, the program skips command execution but fails to free the allocated buffer. Repeating this action causes memory to continuously accumulate. Over time, this can exhaust system memory and terminate the xmllint process, creating a denial-of-service condition on the local system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2435942, 2435943, 2435944, 2435945, 2435946, 2435947, 2435949, 2435948    
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Description OSIDB Bzimport 2026-02-02 11:46:33 UTC 
Memory leak vulnerability in the xmllint interactive shell command parser. The issue is caused by improper memory management when processing input lines that consist solely of whitespace characters. In this scenario, the allocated command buffer is not freed before continuing execution, resulting in a persistent memory leak. By repeatedly supplying large whitespace-only inputs, a local attacker can cause unbounded memory growth, eventually exhausting system resources and triggering an out-of-memory (OOM) condition. This flaw can be exploited without authentication but requires local access to the xmllint shell, leading to a denial-of-service condition.