CVE-2026-63893
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.
Affected versions
Linux kernel versions
4.15
and later are affected. Fixed in
5.10.259,
5.15.210,
6.1.176,
6.6.143,
6.12.93,
6.18.35,
7.0.12,
7.1
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-63893?
CVE-2026-63893 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.15 onward and has been patched in 5.10.259, 5.15.210, 6.1.176 and others. CVE-2026-63893 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-63893?
Yes — CVE-2026-63893 has been patched. Fixed versions include 5.10.259, 5.15.210, 6.1.176 and others. If you are running Linux kernel 4.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-63893 actively exploited?
No — CVE-2026-63893 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.