{"id":"CVE-2026-68278","title":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/dp/mst: fix buffer overflows in sideband chunk accumulation\n\ndrm_dp_sideband_append_payload() has three related bugs when processing\ndevice-provided sideband reply …","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/dp/mst: fix buffer overflows in sideband chunk accumulation\n\ndrm_dp_sideband_append_payload() has three related bugs when processing\ndevice-provided sideband reply …","severity":"high","published":"2026-08-10","updated":"2026-08-23","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-68278","references":[{"url":"https://git.kernel.org/stable/c/1e5827839ad0ceb0079d1560c321fa3656b54f21","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4d5109075a787de28c9e89940f9dee45269f91fa","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/53937a2787d29c7a460e984dc4f20ff6ac91dc65","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/55bd5e685bda455b9b50c835f8c8442d52a344a3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a6366b551079c79bf7bdbadd74c97358bcfe2d58","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d4e05dedb252ed3e540a0c9be511e427f098110a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef0dbcc200c3389f1f781ab181932a97e54b51af","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef2ecb6cf268debf3890df99fea01b6452dcf78e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68278.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-68278"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2513287"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68278"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68278"},{"url":"https://lore.kernel.org/linux-cve-announce/2026081025-CVE-2026-68278-ddb6@gregkh/T"},{"url":"https://access.redhat.com/errata/RHSA-2026:81552"},{"url":"https://access.redhat.com/errata/RHSA-2026:82806"},{"url":"https://access.redhat.com/errata/RHSA-2026:82807"},{"url":"https://access.redhat.com/errata/RHSA-2026:88477"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00238,"epssPercentile":0.14743,"ingestedAt":"2026-08-23T13:48:06.902Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 8","enterprise_linux 9"],"cvss":7.3,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","cvssSource":"vendor","cwe":["CWE-120"],"patched":["enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_nfv_v_8","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_rt_v_8","enterprise_linux_real_time_v_9"],"slug":"CVE-2026-68278","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndrm/dp/mst: fix buffer overflows in sideband chunk accumulation\n\ndrm_dp_sideband_append_payload() has three related bugs when processing\ndevice-provided sideband reply data:\n\n1. Zero-length curchunk_len underflow: msg_len is a 6-bit field taken\n   directly from the DP sideband header. If a device sends msg_len=0,\n   curchunk_len is set to zero. The condition (curchunk_idx >= curchunk_len)\n   is immediately true, and curchunk_len-1 wraps to 255 (u8 underflow).\n   drm_dp_msg_data_crc4() reads 255 bytes from chunk[48], then memcpy()\n   writes 255 bytes into msg[], both far out of bounds.\n\n2. chunk[48] overflow: curchunk_len can reach 63 (6-bit field). chunk[] is\n   only 48 bytes. Multi-iteration payload assembly appends 16-byte blocks\n   until curchunk_idx reaches curchunk_len, writing up to 15 bytes past\n   the end of chunk[] into msg[].\n\n3. msg[256] overflow: each chunk contributes (curchunk_len-1) bytes to\n   msg[]. No check ensures curlen + (curchunk_len-1) stays within msg[256],\n   so the memcpy can spill into adjacent struct fields.\n\nAll three are reachable from any DP MST device that can forge sideband\nreply messages on a physical connection.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68278.json)\n- **RHSA-2026:81552** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:81552)\n- **RHSA-2026:82806** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82806)\n- **RHSA-2026:82807** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82807)\n- **RHSA-2026:88477** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:88477)","depth":"twilight","depthScore":40,"depthScoreParts":{"impact":40.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":214179,"id":"CVE-2026-68278","ts":1790841324970,"field":"cvss","old":null,"new":"7.3"},{"seq":214178,"id":"CVE-2026-68278","ts":1790841324970,"field":"severity","old":"none","new":"high"}]}