{"cve":"CVE-2026-68278","nvd":{"published":"2026-08-10T13:20:16.920","modified":"2026-08-23T13:16:36.020","status":"Received","description":"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 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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/1e5827839ad0ceb0079d1560c321fa3656b54f21","https://git.kernel.org/stable/c/4d5109075a787de28c9e89940f9dee45269f91fa","https://git.kernel.org/stable/c/53937a2787d29c7a460e984dc4f20ff6ac91dc65","https://git.kernel.org/stable/c/55bd5e685bda455b9b50c835f8c8442d52a344a3","https://git.kernel.org/stable/c/a6366b551079c79bf7bdbadd74c97358bcfe2d58"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:47:54.990491175+00:00"},"epss":{"cve":"CVE-2026-68278","score":0.00238,"percentile":0.14872,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}