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Vulnerabilities

Vulnerability · CVE-2026-63962

usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()

Published Jul 19, 2026 · catalog updated Oct 21, 2026 · usb: typec: tcpm: bound

Check if you run it

No confirmed exploitation is on record for CVE-2026-63962. EPSS is 0.21%. Act only if a listed version of usb: typec: tcpm: bound is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (usb: typec: tcpm: bound).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.21%
Remediation
Advisory link
Affected products
Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX modes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX]. But the CMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming ACK with any request the port actually sent. Once port->partner is set, an unsolicited Discover Modes ACK is consumed unconditionally. A broken or malicious port partner can therefore drive altmodes to ALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra Discover Modes ACK with seven VDOs. Because the pre-loop check passes, the loop could then writes up to five entries past altmode_desc[]. For mode_data_prime the next field in struct tcpm_port is the partner_altmode[] pointer array, which then receives partner-chosen SVID/VDO bytes. Move the bound check inside the loop so the array can never be indexed past ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner supplies or how the function was reached.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Linux Kernel4.19.0 → 6.12.93; 6.13.0 → 6.18.35; 6.19.0 → 7.0.12

How to fix CVE-2026-63962

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-63962. EPSS is 0.21%. Act only if a listed version of usb: typec: tcpm: bound is installed.

Which versions are affected?

Compare what you have installed with Kernel 4.19.0 → 6.12.93; 6.13.0 → 6.18.35; 6.19.0 → 7.0.12. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.21%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 19, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOV

  2. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 6.12.93; Kernel fixed in 6.18.35; Kernel fixed in 7.0.12

  3. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 6.12.93; 6.13.0

  4. Oct 21, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOV

Sources

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

CVE-2026-63962: usb: typec: tcpm: bound altmode_desc[] per iteratio… · ZeroDay Findings