{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64320", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.780Z", "datePublished": "2026-07-25T08:49:48.908Z", "dateUpdated": "2026-08-17T04:53:20.999Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:53:20.999Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page\n\nnvmet_execute_disc_get_log_page() validates only the dword alignment\nof the host-supplied Log Page Offset (lpo). The 64-bit offset is then\nadded to a small kzalloc'd buffer that holds the discovery log page\nand the result is passed straight to nvmet_copy_to_sgl(), which\nmemcpy()s data_len bytes out to the host with no source-side bound\ncheck:\n\n u64 offset = nvmet_get_log_page_offset(req->cmd); /* 64-bit host */\n size_t data_len = nvmet_get_log_page_len(req->cmd); /* 32-bit host */\n ...\n if (offset & 0x3) { ... } /* only check */\n ...\n alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req);\n buffer = kzalloc(alloc_len, GFP_KERNEL);\n ...\n status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);\n\nThe Discovery controller is unauthenticated -- nvmet_host_allowed()\nreturns true unconditionally for the discovery subsystem -- so the call\nis reachable pre-authentication by any TCP/RDMA/FC peer that can reach\nthe nvmet target. With a discovery log page of ~1 KiB, an attacker\nrequesting up to 4 KiB starting at offset == alloc_len reads the next\nslab page out and gets its content returned over the fabric (an\nempirical run on a default nvmet-tcp loopback target leaked 81\ncanonical kernel pointers in one Get Log Page response). Pointing the\noffset at unmapped kernel memory faults the in-kernel memcpy and\ncrashes (or panics, on panic_on_oops=1) the target host instead.\n\nThe attacker-controlled source-side offset pattern\n\"nvmet_copy_to_sgl(req, 0, buffer + ATTACKER_OFFSET, ...)\" is unique\nto nvmet_execute_disc_get_log_page in the entire nvmet codebase: every\nother Get Log Page handler in admin-cmd.c either ignores lpo (and\nsilently starts every response at offset 0) or tracks a local\ndestination offset with a fixed source pointer.\n\nValidate the host-supplied offset against the log page size, cap the\ncopy length to what is actually available, and zero-fill any remainder\nof the host transfer buffer. The zero-fill matches the existing\nshort-response pattern in nvmet_execute_get_log_changed_ns()\n(admin-cmd.c) and prevents leaking transport SGL contents when the\nhost asks for more bytes than the log page contains." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable discovery command is remotely reachable through routable NVMe/TCP, as well as NVMe/RDMA and FC transports.\nAC:L - The attacker controls the protocol sequence, transfer length, and aligned 64-bit offset, with no race or condition outside their control.\nPR:N - The discovery subsystem accepts every Host NQN and explicitly skips DH-HMAC-CHAP authentication, making the command reachable pre-authentication.\nUI:N - No victim action is required after the NVMe-oF target port is available.\nS:U - The disclosure and crash affect the vulnerable target kernel within the same security authority.\nC:H - The unbounded offset permits repeated multi-kilobyte kernel heap disclosures; testing cited by the fix exposed 81 canonical kernel pointers in one response.\nI:N - The primitive reads target memory into transport response pages but provides no attacker-selected write to target memory.\nA:H - An offset resolving to unmapped or noncanonical memory faults the in-kernel memcpy, causing an oops or target-host panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/nvme/target/discovery.c" ], "versions": [ { "version": "a07b4970f464f13640e28e16dad6cfa33647cc99", "lessThan": "33b974eb626154ae9348f2bac7de84cb2a3d9dd4", "status": "affected", "versionType": "git" }, { "version": "a07b4970f464f13640e28e16dad6cfa33647cc99", "lessThan": "56c021a0869260d04c4b65d1471936aaf9177114", "status": "affected", "versionType": "git" }, { "version": "a07b4970f464f13640e28e16dad6cfa33647cc99", "lessThan": "a29b316b9bbfd269f323ab4ba9906a894025680f", "status": "affected", "versionType": "git" }, { "version": "a07b4970f464f13640e28e16dad6cfa33647cc99", "lessThan": "53cd102a7a56079b11b897835bd9b94c14e6322c", "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/nvme/target/discovery.c" ], "versions": [ { "version": "4.8", "status": "affected" }, { "version": "0", "lessThan": "4.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "4.8", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4" }, { "url": "https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114" }, { "url": "https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680f" }, { "url": "https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322c" } ], "title": "nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page", "x_generator": { "engine": "bippy-1.2.0" } } } }