Bug 2533904 (CVE-2026-91948)

Summary: CVE-2026-91948 FreeRDP: FreeRDP: Arbitrary code execution via oversized channel messages in SHOW_PROTOCOL
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in FreeRDP. An authenticated client can send specially crafted, oversized messages to the server when the CHANNEL_OPTION_SHOW_PROTOCOL feature is active. This can cause a buffer underflow, leading to corruption of memory and potentially allowing an attacker to execute malicious code on the server.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-15 15:46:45 UTC
FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.