CVE-2026-63962
usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()
Description
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.
INFO
Published Date :
July 19, 2026, 4:17 p.m.
Last Modified :
July 30, 2026, 2:51 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Ensure the Linux kernel is updated.
- Verify array bounds checks in loops.
- Apply security patches for the USB Type-C subsystem.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-63962.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63962 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-63962
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-63962 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63962 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 20, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '845598b154b9a92e9d279fafafa9405c121ae805', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '4505f33dab56c274e82f47f94bf60a8cbf8f4b42', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cbad85b446c06adbc5e5bed565871bb918ce9d32', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3389c149c68c3fea61910ad5d34f7bf3bff44e32', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.93', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.35', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.0.12', 'versionType': 'semver'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.12.93', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.12', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4ab8c18d4d67321cc7b660559de17511d4fc0237', 'lessThan': '845598b154b9a92e9d279fafafa9405c121ae805', 'versionType': 'git'}, {'status': 'affected', 'version': '4ab8c18d4d67321cc7b660559de17511d4fc0237', 'lessThan': '4505f33dab56c274e82f47f94bf60a8cbf8f4b42', 'versionType': 'git'}, {'status': 'affected', 'version': '4ab8c18d4d67321cc7b660559de17511d4fc0237', 'lessThan': 'cbad85b446c06adbc5e5bed565871bb918ce9d32', 'versionType': 'git'}, {'status': 'affected', 'version': '4ab8c18d4d67321cc7b660559de17511d4fc0237', 'lessThan': '3389c149c68c3fea61910ad5d34f7bf3bff44e32', 'versionType': 'git'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.19'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.19', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.93', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.12', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '845598b154b9a92e9d279fafafa9405c121ae805', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '4505f33dab56c274e82f47f94bf60a8cbf8f4b42', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': 'cbad85b446c06adbc5e5bed565871bb918ce9d32', 'versionType': 'git'}, {'status': 'affected', 'version': '1da177e4c3f41524e886b7f1b8a0c1fc7321cac2', 'lessThan': '3389c149c68c3fea61910ad5d34f7bf3bff44e32', 'versionType': 'git'}, {'status': 'affected', 'version': '0', 'lessThan': '6.12.93', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '6.18.35', 'versionType': 'semver'}, {'status': 'affected', 'version': '0', 'lessThan': '7.0.12', 'versionType': 'semver'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'unaffected', 'version': '6.12.93', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.12', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/usb/typec/tcpm/tcpm.c'], 'defaultStatus': 'affected'}] Added Description 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. Added Reference https://git.kernel.org/stable/c/3389c149c68c3fea61910ad5d34f7bf3bff44e32 Added Reference https://git.kernel.org/stable/c/4505f33dab56c274e82f47f94bf60a8cbf8f4b42 Added Reference https://git.kernel.org/stable/c/845598b154b9a92e9d279fafafa9405c121ae805 Added Reference https://git.kernel.org/stable/c/cbad85b446c06adbc5e5bed565871bb918ce9d32