HID: picolcd: clamp eeprom debugfs read to bytes actually received
Published Sep 11, 2026
5.5
MEDIUMCVSS 3.1
EPSS 0.22%
Description
picolcd_debug_eeprom_read() trusts resp->raw_data[2] -- a length byte supplied by the device in its REPORT_EE_DATA reply -- clamped only to the caller's read() count:
ret = resp->raw_data[2]; if (ret > s) ret = s; if (copy_to_user(u, resp->raw_data+3, ret))
It never checks resp->raw_size, the number of bytes picolcd_raw_event() actually copied into the 64-byte raw_data[] of the kmalloc'd struct picolcd_pending. A device (or a spoofed picoLCD) returning a length byte of 0xff, read with a count >= 255, makes copy_to_user() read past raw_data[] into adjacent slab memory and return it to userspace through the debugfs "eeprom" file:
BUG: KASAN: slab-out-of-bounds in _copy_to_user Read of size 255 ... picolcd_debug_eeprom_read+0x214/0x2f0 [hid_picolcd]
The debug-dump path in the same file already validates the device length byte against the received size before trusting it; this read does not. The file is created S_IRUSR (root-only) and a crafted device is needed, so it is neither unprivileged- nor remotely-triggerable.
Clamp the copy length to resp->raw_size - 3 (the payload actually received, minus the 3-byte header), floored at 0 for short replies.
Affected products
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- Version StatusaffectedConstraints
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- Version StatusaffectedConstraints
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- Version
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- Version 2.6.35StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<2.6.35
- Version 5.10.270StatusunaffectedConstraints<=5.10.*
- Version 5.15.221StatusunaffectedConstraints<=5.15.*
- Version 6.1.188StatusunaffectedConstraints<=6.1.*
- Version 6.12.109StatusunaffectedConstraints<=6.12.*
- Version 6.18.50StatusunaffectedConstraints<=6.18.*
- Version 6.6.157StatusunaffectedConstraints<=6.6.*
- Version 7.2.4StatusunaffectedConstraints<=7.2.*
- Version 7.3-rc1StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
Red Hat Enterprise Linux 10
kernel
Fix deferred
Red Hat Enterprise Linux 10
kernel-rt
Fix deferred
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Fix deferred
Red Hat Enterprise Linux 7
kernel-rt
Fix deferred
Red Hat Enterprise Linux 8
kernel
Fix deferred
Red Hat Enterprise Linux 8
kernel-rt
Fix deferred
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
Red Hat OpenShift Container Platform 4
openshift/ose-rhel-coreos-8
Fix deferred
Red Hat OpenShift Container Platform 4
openshift/ose-rhel-coreos-9
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 10 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | n/a |
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (13)
- https://access.redhat.com/security/cve/CVE-2026-89628 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2532179 Issue Tracking
- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89628.mbox
- https://git.kernel.org/stable/c/1a02056c2bf7ef9b5fd05ee6913aeeadb703c443
- https://git.kernel.org/stable/c/471f4a939c66d1d44aece2321807abf609fc9098
- https://git.kernel.org/stable/c/4daf432c94a42e7be6aa10b012b33af5ed9bc118
- https://git.kernel.org/stable/c/65daa322f1021d8206f8032c4cd4c0cb2d26c7c3
- https://git.kernel.org/stable/c/699a3c8b56e168ca19d12722f3f5ef1d6f4b1d84
- https://git.kernel.org/stable/c/8dc662af019158690c470edd2e2857657f700abb
- https://git.kernel.org/stable/c/a3e6e8d7198a9f3861861520a38b673684a1062b
- https://git.kernel.org/stable/c/e9c667395ac1f8024f623250b32bae4c7af9caa0
- https://nvd.nist.gov/vuln/detail/CVE-2026-89628
- https://www.cve.org/CVERecord?id=CVE-2026-89628
Change history (0)
No recorded changes yet.