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Fencer Vulns
no cvss —

CVE-2026-68278 json

drm/dp/mst: fix buffer overflows in sideband chunk accumulation

published 2026-08-10 2 mo ago modified 2026-11-06 2 d ago also EUVD-2026-55379

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

drm/dp/mst: fix buffer overflows in sideband chunk accumulation

drm_dp_sideband_append_payload() has three related bugs when processing device-provided sideband reply data:

1. Zero-length curchunk_len underflow: msg_len is a 6-bit field taken directly from the DP sideband header. If a device sends msg_len=0, curchunk_len is set to zero. The condition (curchunk_idx >= curchunk_len) is immediately true, and curchunk_len-1 wraps to 255 (u8 underflow). drm_dp_msg_data_crc4() reads 255 bytes from chunk[48], then memcpy() writes 255 bytes into msg[], both far out of bounds.

2. chunk[48] overflow: curchunk_len can reach 63 (6-bit field). chunk[] is only 48 bytes. Multi-iteration payload assembly appends 16-byte blocks until curchunk_idx reaches curchunk_len, writing up to 15 bytes past the end of chunk[] into msg[].

3. msg[256] overflow: each chunk contributes (curchunk_len-1) bytes to msg[]. No check ensures curlen + (curchunk_len-1) stays within msg[256], so the memcpy can spill into adjacent struct fields.

All three are reachable from any DP MST device that can forge sideband reply messages on a physical connection.

Patch / fix

  • Linux Linux 5.10.266, 5.15.217, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.101-1
  • linux Debian 14 7.1.6-1
  • linux-6.12 Debian 12 6.12.101-1~deb12u1

debian advisories DEBIAN-CVE-2026-68278

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79

ubuntu advisories UBUNTU-CVE-2026-68278

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-553.173.1.el8_10
  • perf RHEL 8 4.18.0-553.173.1.el8_10
  • bpftool RHEL 8 4.18.0-553.173.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.173.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.173.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.173.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.173.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.173.1.el8_10

red hat advisories RHSA-2026:82807RHSA-2026:82806RHSA-2026:81552

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.81.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.81.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1.150700.17.45.1

suse advisories SUSE-SU-2026:4254-1SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1SUSE-SU-2026:4282-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 10 6.12.0-211.68.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.68.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.68.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.68.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.68.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.68.1.el10_2

almalinux advisories ALSA-2026:88477ALSA-2026:82806ALSA-2026:82807ALSA-2026:81552

  • kernel Rocky Linux 10 6.12.0-211.68.1.el10_2
  • kernel-rt Rocky Linux 8 4.18.0-553.173.1.rt7.514.el8_10
  • kernel Rocky Linux 8 4.18.0-553.173.1.el8_10
  • kernel Rocky Linux 9 5.14.0-687.57.1.el9_8

rocky linux advisories RLSA-2026:88477RLSA-2026:82806RLSA-2026:82807RLSA-2026:81552

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-68278 updated cvss 7.3

kernel: drm/dp/mst: fix buffer overflows in sideband chunk accumulation

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.57.1.el9_8, perf 5.14.0-687.57.1.el9_8, rtla 5.14.0-687.57.1.el9_8, python3-perf 5.14.0-687.57.1.el9_8, kernel-devel-matched 5.14.0-687.57.1.el9_8, kernel-64k-devel-matched 5.14.0-687.57.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:81552
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.68.1.el10_2, perf 6.12.0-211.68.1.el10_2, rtla 6.12.0-211.68.1.el10_2, python3-perf 6.12.0-211.68.1.el10_2, kernel-devel-matched 6.12.0-211.68.1.el10_2, kernel-64k-devel-matched 6.12.0-211.68.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.173.1.el8_10, kernel 4.18.0-553.173.1.el8_10, bpftool 4.18.0-553.173.1.el8_10, kernel-core 4.18.0-553.173.1.el8_10, kernel-tools 4.18.0-553.173.1.el8_10, python3-perf 4.18.0-553.173.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:82807
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.57.1.el9_8, kernel-64k 5.14.0-687.57.1.el9_8, kernel-core 5.14.0-687.57.1.el9_8, kernel-tools 5.14.0-687.57.1.el9_8, kernel-modules 5.14.0-687.57.1.el9_8, kernel-64k-core 5.14.0-687.57.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:81552
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.68.1.el10_2, kernel-64k 6.12.0-211.68.1.el10_2, kernel-core 6.12.0-211.68.1.el10_2, kernel-tools 6.12.0-211.68.1.el10_2, kernel-modules 6.12.0-211.68.1.el10_2, kernel-64k-core 6.12.0-211.68.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.57.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.57.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.57.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.57.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.57.1.el9_8
    fixed: vendor fix RHSA-2026:81552
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.173.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.173.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.173.1.el8_10
    fixed: vendor fix RHSA-2026:82807
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.68.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.68.1.el10_2
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-kvm 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-kvm 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-core 4.18.0-553.173.1.rt7.514.el8_10, +4 more
    fixed: vendor fix RHSA-2026:82806
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.57.1.el9_8, kernel-rt-64k 5.14.0-687.57.1.el9_8, kernel-rt-core 5.14.0-687.57.1.el9_8, kernel-rt-modules 5.14.0-687.57.1.el9_8, kernel-rt-64k-core 5.14.0-687.57.1.el9_8, kernel-rt-debug-core 5.14.0-687.57.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:81552
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.68.1.el10_2, kernel-rt-64k 6.12.0-211.68.1.el10_2, kernel-rt-core 6.12.0-211.68.1.el10_2, kernel-rt-modules 6.12.0-211.68.1.el10_2, kernel-rt-64k-core 6.12.0-211.68.1.el10_2, kernel-rt-debug-core 6.12.0-211.68.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.57.1.el9_8, kernel-rt-core 5.14.0-687.57.1.el9_8, kernel-rt-modules 5.14.0-687.57.1.el9_8, kernel-rt-debug-core 5.14.0-687.57.1.el9_8, kernel-rt-modules-core 5.14.0-687.57.1.el9_8, kernel-rt-debug-modules 5.14.0-687.57.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:81552
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.68.1.el10_2, kernel-rt-core 6.12.0-211.68.1.el10_2, kernel-rt-modules 6.12.0-211.68.1.el10_2, kernel-rt-debug-core 6.12.0-211.68.1.el10_2, kernel-rt-modules-core 6.12.0-211.68.1.el10_2, kernel-rt-debug-modules 6.12.0-211.68.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:88477
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-core 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-debug-modules 4.18.0-553.173.1.rt7.514.el8_10, kernel-rt-modules-extra 4.18.0-553.173.1.rt7.514.el8_10, +2 more
    fixed: vendor fix RHSA-2026:82806
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux for NVIDIA 26 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.