CVE-2024-26995

/// Technical description

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

usb: typec: tcpm: Correct the PDO counting in pd_set

Off-by-one errors happen because nr_snk_pdo and nr_src_pdo are

incorrectly added one. The index of the loop is equal to the number of

PDOs to be updated when leaving the loop and it doesn't need to be added

one.

When doing the power negotiation, TCPM relies on the "nr_snk_pdo" as

the size of the local sink PDO array to match the Source capabilities

of the partner port. If the off-by-one overflow occurs, a wrong RDO

might be sent and unexpected power transfer might happen such as over

voltage or over current (than expected).

"nr_src_pdo" is used to set the Rp level when the port is in Source

role. It is also the array size of the local Source capabilities when

filling up the buffer which will be sent as the Source PDOs (such as

in Power Negotiation). If the off-by-one overflow occurs, a wrong Rp

level might be set and wrong Source PDOs will be sent to the partner

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References