CVE-2026-68278: Linux kernel · drm/dp/mst: fix buffer overflows in sideband chunk accumulation
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in ef2ecb6cf268debf3890df99fea01b6452dcf78e : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:19 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in ef2ecb6cf268debf3890df99fea01b6452dcf78e, ef0dbcc200c3389f1f781ab181932a97e54b51af, d4e05dedb252ed3e540a0c9be511e427f098110a +5
Exploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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.
References
- git.kernel.org/stable/c/ef2ecb6cf268debf3890df99fea01b6452dcf78e (opens in a new tab)
- git.kernel.org/stable/c/d4e05dedb252ed3e540a0c9be511e427f098110a (opens in a new tab)
- git.kernel.org/stable/c/4d5109075a787de28c9e89940f9dee45269f91fa (opens in a new tab)
- git.kernel.org/stable/c/53937a2787d29c7a460e984dc4f20ff6ac91dc65 (opens in a new tab)
- git.kernel.org/stable/c/ef0dbcc200c3389f1f781ab181932a97e54b51af (opens in a new tab)
- git.kernel.org/stable/c/1e5827839ad0ceb0079d1560c321fa3656b54f21 (opens in a new tab)
- git.kernel.org/stable/c/a6366b551079c79bf7bdbadd74c97358bcfe2d58 (opens in a new tab)
- git.kernel.org/stable/c/55bd5e685bda455b9b50c835f8c8442d52a344a3 (opens in a new tab)