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PatchSiren cyber security CVE debrief

CVE-2026-63893 Linux CVE debrief

The Linux kernel was vulnerable to a property leak and out-of-bounds read due to a u32 wrap in the tb_property_entry_valid() function. A malicious XDomain peer could exploit this by providing a specially crafted value and length, allowing them to read attacker-directed memory past the allocation. This vulnerability could potentially allow an attacker to access sensitive information. The Linux kernel maintainers have resolved this issue, and users should update their systems to the latest version to mitigate this vulnerability.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

Users of the Linux kernel should be aware of this vulnerability and take steps to ensure their systems are updated with the latest security patches. System administrators and security teams should review their systems for potential exposure and prioritize updates to mitigate this vulnerability. Additionally, developers and maintainers of systems that rely on the Linux kernel should review the code changes and ensure that their systems are not vulnerable to this issue.

Technical summary

The tb_property_entry_valid() function in the Linux kernel did not properly check for u32 wrap when calculating the sum of entry->value and entry->length. This could allow a malicious XDomain peer to exploit the vulnerability by providing a value of 0xffffff00 and a length of 0x100, causing the sum to wrap to 0 and pass the > block_len check. The tb_property_parse() function would then pass entry->value to parse_dwdata() as a dword offset into the property block, reading attacker-directed memory far past the allocation.

Defensive priority

High

Recommended defensive actions

  • Update Linux kernel to the latest version
  • Review system configurations for potential exposure
  • Monitor system logs for suspicious activity
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-19T16:17:06.710Z and has not been modified since then. The NVD entry is currently Received. There is no additional information available about the vulnerability beyond what is provided in the CVE record and NVD entry. Users should verify the accuracy of the information with the Linux kernel maintainers and review their systems for potential exposure.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T16:17:06.710Z and has not been modified since then.