CVE-2026-68277

Received Received - Intake

Out-of-Bounds Read in Linux Kernel DRM DP MST Sideband Parsers

Publication date: 2026-08-10

Last updated on: 2026-08-23

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: drm/dp/mst: fix OOB reads on 2-byte fields in sideband reply parsers Three sideband reply parsers read 16-bit fields as: val = (raw->msg[idx] << 8) | (raw->msg[idx+1]); and check bounds only after the fact. When idx == raw->curlen, raw->msg[idx+1] reads one byte past the received message data into the following struct fields (curchunk_len, curchunk_idx, curlen). Affected functions: - drm_dp_sideband_parse_enum_path_resources_ack() full_payload_bw_number and avail_payload_bw_number fields - drm_dp_sideband_parse_allocate_payload_ack() allocated_pbn field - drm_dp_sideband_parse_query_payload_ack() allocated_pbn field Fix by using a single combined check (idx + 2 > curlen) before each 2-byte read. Since the check is strictly tighter than idx > curlen, no separate step is needed. [added fixes tag]

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-10

Last Modified

2026-08-23

Generated

2026-08-30

AI Q&A

2026-08-10

EPSS Evaluated

2026-08-29

NVD

CVE-2026-68277

EUVD

EUVD-2026-55378

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability where three sideband reply parsers read 16-bit fields unsafely. They read two bytes without proper bounds checking first, which can lead to reading one byte past the received message data into adjacent struct fields.

Detection Guidance

This vulnerability is specific to the Linux kernel's DRM DisplayPort MST (Multi-Stream Transport) sideband reply parsers. Detection requires checking kernel logs for related errors or examining kernel memory for out-of-bounds reads in the affected functions.

Impact Analysis

This vulnerability could allow an attacker to read sensitive kernel memory or cause undefined behavior by accessing memory outside intended bounds. It may lead to crashes, privilege escalation, or information disclosure in systems using affected Linux kernel components.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it is a low-level memory safety issue in the Linux kernel's DisplayPort MST sideband parser. It may indirectly impact compliance if exploited to cause system instability or data corruption, but no direct regulatory impact is specified.

Mitigation Strategies

Update your Linux kernel to the latest patched version to resolve this issue. If immediate patching is not possible, consider disabling DisplayPort MST functionality as a temporary workaround.

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