CVE-2026-68277

About vulnerability

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]

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

linux @ 4.19.0 (+13 more)

Live-patch status from KernelCare for each operating system.