PT-2026-61208 · Linux · Linux

CVE-2026-63891

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Published

2026-07-19

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Updated

2026-07-19

None

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In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: property: Cap recursion depth in tb property parse dir()
A DIRECTORY entry's value field is used as the dir offset for a recursive call into tb property parse dir() with no depth counter. A crafted peer that chains DIRECTORY entries into a back-reference loop drives the parser until the kernel stack is exhausted and the guard page fires. Any untrusted XDomain peer (cable, dock, in-line inspector, adjacent host) that reaches the PROPERTIES REQUEST control-plane exchange can trigger this without authentication.
Thread a depth counter through tb property parse() and tb property parse dir(), and reject blocks that exceed TB PROPERTY MAX DEPTH = 8. That is comfortably larger than any observed legitimate XDomain layout.
Operators who do not need XDomain host-to-host discovery can disable the path entirely with thunderbolt.xdomain=0 on the kernel command line.
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Related Identifiers

CVE-2026-63891

Affected Products

Linux