Bug 2459317 (CVE-2026-33145)

Summary: CVE-2026-33145 xrdp: xrdp-sesman: xrdp: Arbitrary Command Execution via unsafe handling of AlternateShell parameter
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in xrdp. An authenticated remote user can exploit this vulnerability due to the unsafe handling of the AlternateShell parameter in xrdp-sesman. When the AllowAlternateShell setting is enabled, xrdp executes client-supplied AlternateShell values via /bin/sh -c during session initialization without proper sanitization. This allows an attacker to execute arbitrary commands on the server within the security context of the authenticated user, potentially bypassing normal session restrictions.
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Bug Depends On: 2459615, 2459616    
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Description OSIDB Bzimport 2026-04-17 21:02:03 UTC 
xrdp is an open source RDP server. Versions through 0.10.5 allow an authenticated remote user to execute arbitrary commands on the server due to unsafe handling of the AlternateShell parameter in xrdp-sesman. When the AllowAlternateShell setting is enabled (which is the default when not explicitly configured), xrdp accepts a client-supplied AlternateShell value and executes it via /bin/sh -c during session initialization. This results in shell-interpreted execution of unsanitized, user-controlled input. This behavior effectively provides a scriptable remote command execution primitive over RDP within the security context of the authenticated user, occurring prior to normal window manager startup. This can bypass expected session initialization flows and operational assumptions that restrict execution to interactive desktop environments. This issue has been fixed in version 0.10.6.