CVE-2026-53245

Summary

In the Linux kernel, the following vulnerability has been resolved:

net/802/mrp: fix vector attribute parsing in mrp_pdu_parse_vecattr

In mrp_pdu_parse_vecattr(), vector attribute events are encoded three per byte and valen tracks the number of events left to process.

The parser decrements valen after processing the first and second events from each event byte, but not after processing the third one. When valen is exactly a multiple of three, the loop continues after the last valid event and consumes the next byte as a new event byte, applying a spurious event to the MRP applicant state.

Additionally, when valen is zero the parser unconditionally consumes attrlen bytes as FirstValue and advances the offset, even though per IEEE 802.1ak a VectorAttribute with only a LeaveAllEvent has valen of zero and no FirstValue or Vector fields. This corrupts the offset for subsequent PDU parsing.

Also, when valen exceeds three the loop crosses byte boundaries but the attribute value is not incremented between the last event of one byte and the first event of the next. This causes the first event of the next byte to use the same attribute value as the third event rather than the next consecutive value.

Decrement valen after processing the third event, skip FirstValue consumption when valen is zero, and increment the attribute value at the end of each loop iteration.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < ae65714d96f68bb252eb20085320bdaacab36c00affected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < 36d259711872e3b2f6cd76a4d270c21931c0f35faffected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < cc98717e591a963a616fdf15ecf48eefaf45d758affected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < 6d6e42e8e17f18d61327f8653479c5b5e161ae1daffected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < fd9c3a47c670bec6b18f44454cea023f93b5adb3affected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < 42446ca0f3570663e87183c065e0b4def52dfba2affected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < 6eea6494e542a03cdf755a593b7d74f3f7c260fdaffected
LinuxLinuxfebf018d22347b5df94066bca05d0c11a84e839d < 7561c7fbc694308da73300f036719e63e42bf0b4affected
LinuxLinux3.9affected
LinuxLinux0 < 3.9unaffected
LinuxLinux5.10.259 <= 5.10.*unaffected
LinuxLinux5.15.210 <= 5.15.*unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.94 <= 6.12.*unaffected
LinuxLinux6.18.36 <= 6.18.*unaffected
LinuxLinux7.0.13 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References