{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49977", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-06-18T10:57:27.385Z", "datePublished": "2025-06-18T11:00:39.871Z", "dateUpdated": "2026-08-05T08:56:59.013Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:56:59.013Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead\n\nftrace_startup does not remove ops from ftrace_ops_list when\nftrace_startup_enable fails:\n\nregister_ftrace_function\n ftrace_startup\n __register_ftrace_function\n ...\n add_ftrace_ops(&ftrace_ops_list, ops)\n ...\n ...\n ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1\n ...\n return 0 // ops is in the ftrace_ops_list.\n\nWhen ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything:\nunregister_ftrace_function\n ftrace_shutdown\n if (unlikely(ftrace_disabled))\n return -ENODEV; // return here, __unregister_ftrace_function is not executed,\n // as a result, ops is still in the ftrace_ops_list\n __unregister_ftrace_function\n ...\n\nIf ops is dynamically allocated, it will be free later, in this case,\nis_ftrace_trampoline accesses NULL pointer:\n\nis_ftrace_trampoline\n ftrace_ops_trampoline\n do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!\n\nSyzkaller reports as follows:\n[ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b\n[ 1203.508039] #PF: supervisor read access in kernel mode\n[ 1203.508798] #PF: error_code(0x0000) - not-present page\n[ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0\n[ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI\n[ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G B W 5.10.0 #8\n[ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014\n[ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0\n[ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 <48> 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00\n[ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246\n[ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866\n[ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b\n[ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07\n[ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399\n[ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008\n[ 1203.525634] FS: 00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000\n[ 1203.526801] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0\n[ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n\nTherefore, when ftrace_startup_enable fails, we need to rollback registration\nprocess and remove ops from ftrace_ops_list." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is reached through local ftrace registration paths (tracefs function tracer/instances/set_ftrace_filter probes, or perf_event_open function tracing) that call register_ftrace_function → ftrace_startup; there is no network or adjacent-protocol entry point.\nAC:L - An attacker who can drive ftrace registration fully controls creating dynamic ops, forcing the ftrace_startup_enable failure/disable window (as syzkaller did), ignoring failed unregister, and freeing the ops, then triggering is_ftrace_trampoline via stack unwind; success is not left to uncontrolled third-party state.\nPR:L - Worst reasonable deployments grant TRACE_MODE_WRITE (0640) via tracefs gid=tracing (Android atrace/perfetto, ChromeOS) or CAP_PERFMON for function tracing; these are delegatable low privileges, not init-namespace root, and are not obtainable only via full CAP_SYS_ADMIN.\nUI:N - The attacker creates instances/enables the function tracer (or opens a perf ftrace event), triggers the dead-ftrace register/unregister/free sequence, and causes stack unwinding themselves with no separate victim action.\nS:U - The dangling ftrace_ops UAF and any resulting memory corruption or oops remain inside the host kernel's privilege domain; this is not a VM escape, IOMMU bypass, or other cross-authority boundary crossing.\nC:H - Dynamically allocated ftrace_ops remain linked on ftrace_ops_list after free, so is_ftrace_trampoline's list walk is a use-after-free that can be reclaimed/sprayed to disclose kernel memory through trampoline/next field reads.\nI:H - The same UAF of struct ftrace_ops (including func/trampoline pointers) is heap-sprayable into type confusion and control-flow hijack when list walkers consume the reclaimed object, matching CVSS guidance that exploitable UAFs are Integrity High.\nA:H - The confirmed syzkaller outcome is a kernel NULL pointer dereference oops in is_ftrace_trampoline while walking the stale ops list, which panics or takes down the system and can be re-triggered after the dangling entry is left behind." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/ftrace.c" ], "versions": [ { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "8569b4ada1e0b9bfaa125bd0c0967918b6560fa2", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "4c34a2a6c9927c239dd2e295a03d49b37b618d2c", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "ddffe882d74ef43a3494f0ab0c24baf076c45f96", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "934e49f7d696afdae9f979abe3f308408184e17b", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "dbd8c8fc60480e3faa3ae7e27ebe03371ecd1b77", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "e4ae97295984ff1b9b340ed18ae1b066f36b7835", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "d81bd6671f45fde4c3ac7fd7733c6e3082ae9d8e", "status": "affected", "versionType": "git" }, { "version": "8a56d7761d2d041ae5e8215d20b4167d8aa93f51", "lessThan": "c3b0f72e805f0801f05fa2aa52011c4bfc694c44", "status": "affected", "versionType": "git" }, { "version": "969a08e9048ddd0d655a19e692673cdb95116ce6", "status": "affected", "versionType": "git" }, { "version": "51d351d5b949ae7204696ada7ef502ed34d34fb0", "status": "affected", "versionType": "git" }, { "version": "2940c25bec92f40a3f7f32504b8ea115d1701892", "status": "affected", "versionType": "git" }, { "version": "189f4e672fc1c086f78818affc810ef29dda42a3", "status": "affected", "versionType": "git" }, { "version": "3.2.54", "lessThan": "3.3", "status": "affected", "versionType": "semver" }, { "version": "3.4.72", "lessThan": "3.5", "status": "affected", "versionType": "semver" }, { "version": "3.10.22", "lessThan": "3.11", "status": "affected", "versionType": "semver" }, { "version": "3.12.3", "lessThan": "3.13", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/ftrace.c" ], "versions": [ { "version": "3.13", "status": "affected" }, { "version": "0", "lessThan": "3.13", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.327", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.292", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.257", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.212", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.141", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.65", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.19.7", "lessThanOrEqual": "5.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.0", "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": "3.13", "versionEndExcluding": "4.9.327" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "4.14.292" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "4.19.257" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "5.4.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "5.10.141" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "5.15.65" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "5.19.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.72" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/8569b4ada1e0b9bfaa125bd0c0967918b6560fa2" }, { "url": "https://git.kernel.org/stable/c/4c34a2a6c9927c239dd2e295a03d49b37b618d2c" }, { "url": "https://git.kernel.org/stable/c/ddffe882d74ef43a3494f0ab0c24baf076c45f96" }, { "url": "https://git.kernel.org/stable/c/934e49f7d696afdae9f979abe3f308408184e17b" }, { "url": "https://git.kernel.org/stable/c/dbd8c8fc60480e3faa3ae7e27ebe03371ecd1b77" }, { "url": "https://git.kernel.org/stable/c/e4ae97295984ff1b9b340ed18ae1b066f36b7835" }, { "url": "https://git.kernel.org/stable/c/d81bd6671f45fde4c3ac7fd7733c6e3082ae9d8e" }, { "url": "https://git.kernel.org/stable/c/c3b0f72e805f0801f05fa2aa52011c4bfc694c44" } ], "title": "ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead", "x_generator": { "engine": "bippy-1.2.0" } } } }