CVE-2026-93067
drm/bridge: tc358767: clamp the reported AUX read size to the request
Published Sep 17, 2026
CVSS n/a
EPSS < 1%
KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:
drm/bridge: tc358767: clamp the reported AUX read size to the request
tc_aux_transfer() clamps an AUX read to the payload limit:
size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size);
After the transfer it replaces size with the byte count the controller
reports in AUX_BYTES:
if (size)
size = FIELD_GET(AUX_BYTES, auxstatus);
AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it
back to the request. tc_aux_read_data() reads that many bytes into the
16-byte auxrdata stack buffer, then copies them into the caller buffer. A
reported count of 255 makes the read run to 256 bytes and overruns both.
The controller should never report more than it was asked to transfer, so
this is defense in depth rather than a live hole. The reported count is
only lightly trusted, and the check is cheap. Clamp it back to the request,
the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge:
ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer").
drm/bridge: tc358767: clamp the reported AUX read size to the request
tc_aux_transfer() clamps an AUX read to the payload limit:
size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size);
After the transfer it replaces size with the byte count the controller
reports in AUX_BYTES:
if (size)
size = FIELD_GET(AUX_BYTES, auxstatus);
AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it
back to the request. tc_aux_read_data() reads that many bytes into the
16-byte auxrdata stack buffer, then copies them into the caller buffer. A
reported count of 255 makes the read run to 256 bytes and overruns both.
The controller should never report more than it was asked to transfer, so
this is defense in depth rather than a live hole. The reported count is
only lightly trusted, and the check is cheap. Clamp it back to the request,
the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge:
ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer").
Affected Products
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CVE record
-
NVD configurations
No data
-
Red Hat packages
No data
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
| Vendor | Product | Versions | ||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux Kernel |
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| Linux | Linux Kernel |
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Remediation
Tracking
Advisories
| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-4817-1 | linux-6.12 security update |
| Debian DLA |
DLA-4841-1 | linux security update |
 Debian DSA |
DSA-6528-1 | linux security update |
 Ubuntu USN |
USN-8961-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9019-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-9020-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9022-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9023-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9024-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9025-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9026-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-9029-1 | Linux kernel (Raspberry Pi) vulnerabilities |
| Ubuntu USN |
USN-9039-1 | Linux kernel (Azure CVM) vulnerabilities |
| Ubuntu USN |
USN-9040-1 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
| Ubuntu USN |
USN-9066-1 | Linux kernel (HWE) vulnerabilities |
| Ubuntu USN |
USN-9091-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Metrics
No CVSS v4.0
No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.177% probability within 30 days)
Key SSVC decision points have not yet been added.
References
History
Sep 19, 2026 12:45 PM
Weaknesses updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 CWE-120 |
Sep 17, 2026 4:30 PM
Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: drm/bridge: tc358767: clamp the reported AUX read size to the request tc_aux_transfer() clamps an AUX read to the payload limit: size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size); After the transfer it replaces size with the byte count the controller reports in AUX_BYTES: if (size) size = FIELD_GET(AUX_BYTES, auxstatus); AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it back to the request. tc_aux_read_data() reads that many bytes into the 16-byte auxrdata stack buffer, then copies them into the caller buffer. A reported count of 255 makes the read run to 256 bytes and overruns both. The controller should never report more than it was asked to transfer, so this is defense in depth rather than a live hole. The reported count is only lightly trusted, and the check is cheap. Clamp it back to the request, the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge: ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer"). | |
| Title | drm/bridge: tc358767: clamp the reported AUX read size to the request | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
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