{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63794", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.012Z", "datePublished": "2026-07-19T12:02:03.488Z", "dateUpdated": "2026-08-17T04:50:58.924Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:50:58.924Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Fix page overflow in sev_dbg_crypt() for ENCRYPT path\n\nIn sev_dbg_crypt(), the per-iteration transfer length is bounded by\nthe source page offset (PAGE_SIZE - s_off) but not by the destination\npage offset (PAGE_SIZE - d_off). When d_off > s_off, the encrypt\npath (__sev_dbg_encrypt_user) performs a read-modify-write using a\nsingle-page intermediate buffer (dst_tpage):\n\n 1. __sev_dbg_decrypt() expands the size to round_up(len + (d_off & 15), 16)\n before issuing the PSP command. If len + (d_off & 15) > PAGE_SIZE,\n the PSP writes beyond the end of the 4096-byte dst_tpage allocation.\n\n 2. The subsequent memcpy()/copy_from_user() into\n page_address(dst_tpage) + (d_off & 15) of 'len' bytes overflows\n by up to 15 bytes under the same condition.\n\nTrigger example: s_off = 0, d_off = 1, debug.len = PAGE_SIZE -\nthe PSP is instructed to write round_up(4097, 16) = 4112 bytes to\na 4096-byte buffer.\n\nFix by also bounding len by (PAGE_SIZE - d_off), the same check that\nsev_send_update_data() already performs for its single-page guest\nregion.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in sev_dbg_crypt+0x993/0xd10 [kvm_amd]\n Write of size 4095 at addr ff110062293bb009 by task sev_dbg_test/228214\n\n CPU: 96 UID: 0 PID: 228214 Comm: sev_dbg_test Tainted: G U W 7.0.0-smp--5ce9b0c48211-dbg #156 PREEMPTLAZY\n Tainted: [U]=USER, [W]=WARN\n Hardware name: Google Astoria/astoria, BIOS 0.20250817.1-0 08/25/2025\n Call Trace:\n \n dump_stack_lvl+0x54/0x70\n print_report+0xbc/0x260\n kasan_report+0xa2/0xd0\n kasan_check_range+0x25f/0x2c0\n __asan_memcpy+0x40/0x70\n sev_dbg_crypt+0x993/0xd10 [kvm_amd]\n sev_mem_enc_ioctl+0x33c/0x450 [kvm_amd]\n kvm_vm_ioctl+0x65d/0x6d0 [kvm]\n __se_sys_ioctl+0xb2/0x100\n do_syscall_64+0xe8/0x870\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n \n\n The buggy address belongs to the physical page:\n page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7fe72b6a0 pfn:0x62293bb\n memcg:ff11000112827d82\n flags: 0x1400000000000000(node=1|zone=1)\n raw: 1400000000000000 0000000000000000 dead000000000122 0000000000000000\n raw: 00000007fe72b6a0 0000000000000000 00000001ffffffff ff11000112827d82\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n ff110062293bbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n ff110062293bbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n >ff110062293bc000: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n ^\n ff110062293bc080: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n ff110062293bc100: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n ==================================================================\n Disabling lock debugging due to kernel taint\n\n[sean: add sample KASAN splat, Fixes, and stable@]" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/sev.c" ], "versions": [ { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "f701ae476cb92a3a3d8844bb39bb63b4512684c8", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "64f2449841ffc7d203183aa4c748c9c77951ecc5", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "9349b50f4b11f135fe73b56cb2c2c872d8bc71d7", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "889c2a9c59897ca912bf39df5bb92555a0a13df4", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "e1a0fe288dee07b7da25a71e007c1ecd1080315b", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "720949ed666f34ff28ffdfe1471a5861d1e41fdf", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "2753a097d1fe24c4351c608048612c74108aa89f", "status": "affected", "versionType": "git" }, { "version": "24f41fb23a39bc2b6f190dcef35a5813a4bf183a", "lessThan": "78ee2d50185a037b3d2452a97f3dad69c3f7f389", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/sev.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.260", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.211", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.177", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.144", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.95", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.38", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.3", "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": "4.16", "versionEndExcluding": "5.10.260" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.15.211" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.1.177" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.6.144" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.12.95" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.18.38" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.1.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f701ae476cb92a3a3d8844bb39bb63b4512684c8" }, { "url": "https://git.kernel.org/stable/c/64f2449841ffc7d203183aa4c748c9c77951ecc5" }, { "url": "https://git.kernel.org/stable/c/9349b50f4b11f135fe73b56cb2c2c872d8bc71d7" }, { "url": "https://git.kernel.org/stable/c/889c2a9c59897ca912bf39df5bb92555a0a13df4" }, { "url": "https://git.kernel.org/stable/c/e1a0fe288dee07b7da25a71e007c1ecd1080315b" }, { "url": "https://git.kernel.org/stable/c/720949ed666f34ff28ffdfe1471a5861d1e41fdf" }, { "url": "https://git.kernel.org/stable/c/2753a097d1fe24c4351c608048612c74108aa89f" }, { "url": "https://git.kernel.org/stable/c/78ee2d50185a037b3d2452a97f3dad69c3f7f389" } ], "title": "KVM: SVM: Fix page overflow in sev_dbg_crypt() for ENCRYPT path", "x_generator": { "engine": "bippy-1.2.0" } } } }