[CVE-2026-53196][IMPORTANT] USB: serial: io_ti: fix heap overflow in get_manuf_info()

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-53196
Priority: IMPORTANT
AL-KERNEL base severity: IMPORTANT
KPANIC flag: YES
Patch: USB: serial: io_ti: fix heap overflow in get_manuf_info()
Commit: e168db91442b94e64fa82a7dd297983d48ea5cc0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e168db91442b94e64fa82a7dd297983d48ea5cc0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53196
Analysis date: Thu, 25 Jun 2026 06:58:04 -0400
ActionableScore: 7
ActionableScore lower bound: 6
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A malicious USB device can provide an oversized io_ti EEPROM descriptor length, causing a large kernel heap overflow in get_manuf_info(), with likely DoS and plausible worst-case confidentiality or integrity impact.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-53196 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53196

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: IMPORTANT
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-53196	IMPORTANT	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';CWE-122;*CWE-787;CWE-125;*CWE-20;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '6.8';DESCR 'get_manuf_info() in the USB serial io_ti driver can copy a device controlled EEPROM descriptor length into a 10 byte heap buffer without checking that the descriptor Size matches sizeof(struct edge_ti_manuf_descriptor). A malicious USB device can advertise a Size value up to the TI I2C image limit and trigger a large heap overflow when the device is attached and the driver reads the descriptor. For the CVSS the PR:N is used because the attacker does not need an account on the host and only needs the malicious USB device to be processed by the vulnerable driver. The issue is not remotely reachable over IP networks and is best modeled as a physical peripheral attack. Impact is at least kernel crash DoS and because this is a kernel heap overflow with device controlled input, confidentiality and integrity impact are plausible in worst case and the issue requires manual review.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	OOB USB INIT PRINTF-TTY SIMPLEFIX ERRORPATH HARDWARE LINUS KPANIC  KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=7
ActionableScoreLower=6

## 1. ActionableScore

* Conservative score: 6
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Triggered signals:

* Firmware-mediated external influence: +1
  The overflow length comes from device-controlled EEPROM data on a USB device.

* Memory corruption, strong corruption primitive: +2
  The bug is a kernel heap overflow into a 10 byte buffer with a device-controlled size up to about 16 KB.

* Privilege escalation plausible: +2
  Kernel heap overflow with attacker-controlled peripheral input can plausibly be exploitable beyond DoS, although no concrete exploit chain is shown.

* Reliable kernel crash / strong DoS: +1
  The commit directly describes a large heap overflow and additional out-of-bounds access during checksum validation.

* Privileged kernel/device-management memory corruption path: +1
  The corruption occurs in a trusted USB serial driver probe/device initialization path.

* Confidentiality impact plausible: +1
  Heap corruption may plausibly expose or influence adjacent kernel objects in worst case.

* Integrity impact plausible: +1
  A large heap overwrite may plausibly corrupt kernel objects or control data.

Subtracted signals:

* Physical-only or rare hardware-only condition: -2
  The attacker normally needs to attach or emulate a malicious USB device.

* Rare AND difficult-to-reach subsystem/configuration: -1
  The affected io_ti USB serial driver is device-specific and not a broad default network or filesystem path.

Paranoid difference:

* Availability impact realistic: +1
  For the paranoid score, the bug is treated as an easy host-wide crash once a malicious matching USB device is processed.

## 3. Reachability analysis

The attacker does not need a local account on the host. The realistic trigger is physical or peripheral-level access: plug in or emulate a malicious USB device handled by the io_ti driver. This is not IP-network reachable.

Namespaces and containers do not materially reduce the attacker requirement because the vulnerable path is in host USB device handling, not a namespaced syscall interface. The path depends on the driver being present and bound to the device, so exposure is narrower than common USB core code but still security-relevant for systems that accept untrusted USB peripherals.

## 4. Severity interpretation

This is not an ordinary Moderate resource leak or validation-only bug. It is a real kernel heap overflow with attacker-controlled device data and a large overwrite size.

Realistic impact is at least local physical DoS via kernel crash. Theoretical impact includes privilege escalation or kernel code execution because the primitive is heap memory corruption in kernel context, but the patch does not demonstrate allocator grooming, object replacement, or a reliable exploit chain. This makes it an Actionable Moderate at minimum and a Strong Important candidate for manual triage.

## 5. One-sentence report phrase

A malicious USB device can provide an oversized io_ti EEPROM descriptor length, causing a large kernel heap overflow in get_manuf_info(), with likely DoS and plausible worst-case confidentiality or integrity impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the issue is a device-controlled kernel heap overflow, not a crash-only NULL dereference or resource leak. Even though reachability is physical and driver-specific, the corruption primitive is strong enough to require manual security review.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: USB: serial: io_ti: fix heap overflow in get_manuf_info()
Commit: e168db91442b94e64fa82a7dd297983d48ea5cc0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e168db91442b94e64fa82a7dd297983d48ea5cc0

Commit description:

get_manuf_info() reads le16_to_cpu(rom_desc->Size) bytes from the
device I2C EEPROM into a buffer allocated with kmalloc_obj(), which
is sizeof(struct edge_ti_manuf_descriptor) = 10 bytes.

The Size field comes from the device and is only validated (in
check_i2c_image()) to make sure the descriptor fits within
TI_MAX_I2C_SIZE (16384 bytes), not against the destination buffer size.
A malicious USB device can therefore set Size to any value up to 16377,
causing a heap overflow of up to 16367 bytes when plugged into a host
running this driver.

valid_csum() is called after read_rom() and also iterates
buffer[0..Size-1], compounding the out-of-bounds access.

Fix by rejecting descriptors with unexpected length before calling
read_rom().

Fixes: 1da177e ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
[ johan: amend commit message; also check for short descriptors ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/usb/serial/io_ti.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e168db91442b94e64fa82a7dd297983d48ea5cc0

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-53196 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53196

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 6.8

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 6
  Paranoid ActionableScore: 7

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: IMPORTANT
KPANIC detected for this report: YES
Published priority for this report (same as in Subject): IMPORTANT

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).