Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5 drm/dp/mst drm_dp_sideband_append_payload out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k1.00

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5. This vulnerability affects the function drm_dp_sideband_append_payload of the file drm/dp/mst. Executing a manipulation can lead to out-of-bounds. This vulnerability is handled as CVE-2026-68278. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5. This vulnerability affects the function drm_dp_sideband_append_payload of the file drm/dp/mst. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-68278 since 07/30/2026. The exploitation appears to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/10/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc1 eliminates this vulnerability. Applying the patch 53937a2787d29c7a460e984dc4f20ff6ac91dc65/ef0dbcc200c3389f1f781ab181932a97e54b51af/1e5827839ad0ceb0079d1560c321fa3656b54f21/a6366b551079c79bf7bdbadd74c97358bcfe2d58/55bd5e685bda455b9b50c835f8c8442d52a344a3 is able to eliminate this problem.

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Productinfo

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Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc1
Patch: 53937a2787d29c7a460e984dc4f20ff6ac91dc65/ef0dbcc200c3389f1f781ab181932a97e54b51af/1e5827839ad0ceb0079d1560c321fa3656b54f21/a6366b551079c79bf7bdbadd74c97358bcfe2d58/55bd5e685bda455b9b50c835f8c8442d52a344a3

Timelineinfo

07/30/2026 CVE reserved
08/10/2026 +11 days Advisory disclosed
08/10/2026 +0 days VulDB entry created
08/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-68278 (🔒)
GCVE (CVE): GCVE-0-2026-68278
GCVE (VulDB): GCVE-100-387676

Entryinfo

Created: 08/10/2026 17:29
Changes: 08/10/2026 17:29 (59)
Complete: 🔍
Cache ID: 216::103

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