{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64527", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.794Z", "datePublished": "2026-07-25T09:20:51.078Z", "dateUpdated": "2026-07-25T09:20:51.078Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-07-25T09:20:51.078Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/hyperv: validate VMBus packet size in receive callback\n\nhyperv_receive_sub() reads msg->vid_hdr.type and dispatches into one\nof four message-type branches without knowing how many bytes the host\nwrote into hv->recv_buf. The completion path then runs\nmemcpy(hv->init_buf, msg, VMBUS_MAX_PACKET_SIZE), so the consumer that\nwakes on wait_for_completion_timeout() can read up to 16 KiB of\nresidue from a prior message as if it were the response payload.\n\nPass bytes_recvd into hyperv_receive_sub() and reject any packet that\ndoes not cover the pipe + synthvid header. A single switch on\nmsg->vid_hdr.type then computes the type-specific payload size: the\nthree completion-driving types (SYNTHVID_VERSION_RESPONSE,\nSYNTHVID_RESOLUTION_RESPONSE, SYNTHVID_VRAM_LOCATION_ACK) fall through\nto a shared exit that requires that size before memcpy/complete, while\nSYNTHVID_FEATURE_CHANGE validates its own payload and returns before\nreading is_dirt_needed. Unknown types are dropped.\n\nSYNTHVID_RESOLUTION_RESPONSE is variable length: the host fills\nresolution_count entries, not the full SYNTHVID_MAX_RESOLUTION_COUNT\narray. Validate the fixed prefix first so resolution_count can be\nread, bound it against the array, then require only the count-sized\narray, so the shorter responses the host actually sends are accepted.\n\nOnly run the sub-handler when vmbus_recvpacket() returned success. The\nmemcpy length is bytes_recvd, which is bounded by VMBUS_MAX_PACKET_SIZE\nonly on a successful receive; on -ENOBUFS vmbus_recvpacket() instead\nreports the required length, which can exceed hv->recv_buf, so copying\nbytes_recvd would read and write past the 16 KiB buffers. Gating on the\nsuccess return keeps the copy bounded. The nonzero-return path is itself\na malformed-message case and is now logged rather than silently skipped;\nchannel recovery is not attempted.\n\nRejected packets are reported via drm_err_ratelimited() rather than\nsilently dropped, matching the CoCo-hardened pattern in\nhv_kvp_onchannelcallback()." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/hyperv/hyperv_drm_proto.c" ], "versions": [ { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "57d5d697642e05d5dd2d40660817765943dd709f", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "f5251226551bfec98c4705641b6f94ff1f238d91", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "049a6b474823049fe60212f25f26e4b30f44ee8f", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "588c84b461393ff1998ac7b97b04f953f642e0df", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "164dc7bf17609340233c6bf4f66bb7c7008a0511", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "c8974d96b6a5496f33dc69a3ce28a7bf5078def4", "status": "affected", "versionType": "git" }, { "version": "76c56a5affeba1e163b66b9d8cc192e6154466f0", "lessThan": "7f87763f47a3c22fb50265a00619ef10f2394b18", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/hyperv/hyperv_drm_proto.c" ], "versions": [ { "version": "5.14", "status": "affected" }, { "version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/57d5d697642e05d5dd2d40660817765943dd709f" }, { "url": "https://git.kernel.org/stable/c/f5251226551bfec98c4705641b6f94ff1f238d91" }, { "url": "https://git.kernel.org/stable/c/049a6b474823049fe60212f25f26e4b30f44ee8f" }, { "url": "https://git.kernel.org/stable/c/588c84b461393ff1998ac7b97b04f953f642e0df" }, { "url": "https://git.kernel.org/stable/c/164dc7bf17609340233c6bf4f66bb7c7008a0511" }, { "url": "https://git.kernel.org/stable/c/c8974d96b6a5496f33dc69a3ce28a7bf5078def4" }, { "url": "https://git.kernel.org/stable/c/7f87763f47a3c22fb50265a00619ef10f2394b18" } ], "title": "drm/hyperv: validate VMBus packet size in receive callback", "x_generator": { "engine": "bippy-1.2.0" } } } }