Bug 2502396 (CVE-2026-63893) - CVE-2026-63893 kernel: thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()
Summary: CVE-2026-63893 kernel: thunderbolt: property: Reject u32 wrap in tb_property_...
Keywords:
Status: NEW
Alias: CVE-2026-63893
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 16:05 UTC by OSIDB Bzimport
Modified: 2026-07-21 20:31 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-07-19 16:05:57 UTC
In the Linux kernel, the following vulnerability has been resolved:

thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()

entry->value is u32 and entry->length is u16; the sum is performed in
u32 and wraps.  A malicious XDomain peer can pick
value = 0xffffff00, length = 0x100 so the sum 0x100000000 wraps to 0
and passes the > block_len check.  tb_property_parse() then passes
entry->value to parse_dwdata() as a dword offset into the property
block, reading attacker-directed memory far past the allocation.

For TEXT-typed entries with the "deviceid" or "vendorid" keys this
lands in xd->device_name / xd->vendor_name and is readable back via
the per-XDomain device_name / vendor_name sysfs attributes; the leak
is NUL-bounded (kstrdup() stops at the first zero byte) and
untargeted (the attacker picks a delta, not an absolute address).
DATA-typed entries are parsed into property->value.data but not
generically surfaced to userspace.

Use check_add_overflow() so a wrapped sum is rejected.


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