{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99235", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.402Z", "datePublished": "2026-11-02T16:06:41.510Z", "dateUpdated": "2026-11-03T19:13:03.627Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-11-03T19:13:03.627Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Save the event file instead of the compatible histogram\n\ncreate_field_var_hist() creates a histogram on the matched event to\nsupply a field variable, and records it on the target so it can be torn\ndown later:\n\n\thist_data = find_compatible_hist(target_hist_data, file);\n\t...\n\t/* Save the compatible histogram information */\n\tvar_hist->hist_data = hist_data;\n\nhist_data is not the histogram it creates. It is one that was already\nthere, whose keys the new one copies. The saved pointer has a single\nuser, unregister_field_var_hists(), which runs when the target is\nremoved:\n\n\tfile = hist_data->field_var_hists[i]->hist_data->event_file;\n\nfind_compatible_hist() matches on keys alone, so it can pick one with no\nvariables of its own. check_var_refs() then returns false and the user\ncan remove it while the target still points at it:\n\n BUG: KASAN: slab-use-after-free in event_hist_trigger_free+0x2b2/0x320\n Read of size 8 at addr ffff8880093b90e0 by task init/1\n\n Freed by task 1:\n kfree+0x154/0x420\n event_hist_trigger_free+0x1d5/0x320\n event_hist_trigger_parse+0x35f3/0x69e0\n trigger_process_regex+0x1a6/0x250\n\nSave the event file instead. It is all the dereference ever wanted, and\nit does not go away when the user removes a trigger." } ], "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 attacker-controlled hist text is written locally to events///trigger: event_trigger_write() -> trigger_process_regex() -> event_hist_trigger_parse() -> create_actions()/onmatch_create() -> trace_action_create_field_var() -> create_field_var_hist(). No remote protocol carries the keys or onmatch() field names that make find_compatible_hist() save the dangling pointer.\nAC:L - The attacker writes a keys-only hist on event A, an onmatch().trace() hist on event B so create_field_var_hist() stores A's hist_data, then '!hist' on A and on B. find_compatible_hist() matches keys only, so check_var_refs() lets A be removed; event_mutex serializes every write, with no race or victim state.\nPR:L - create_field_var_hist() is reached only after writes to a TRACE_MODE_WRITE (0640) trigger file and to synthetic_events; event_trigger_regex_open() and the synth file enforce LOCKDOWN_TRACEFS and DAC, not capable(). tracefs_parse_param() uid= is applied by tracefs_apply_options() onto those inodes, so a delegated non-root tracing owner can run the onmatch() sequence; userns cannot mount tracefs.\nUI:N - The attacker performs the compatible-hist write, the onmatch().trace() write that calls create_field_var_hist(), and both '!hist' removals themselves. No other user must mount media, open a file, or enable tracing.\nS:U - The slab use-after-free of the compatible hist_trigger_data is in the host kernel's tracing heap (event_hist_trigger_free()/unregister_field_var_hists()). It does not cross a VM, IOMMU, or sandbox boundary.\nC:H - unregister_field_var_hists() reads field_var_hists[i]->hist_data->event_file from the hist_trigger_data that event_hist_trigger_free() already kfree'd (KASAN 8-byte read). After reclaiming that slab, the attacker controls the pointer then walked as a trace_event_file, a use-after-free read primitive.\nI:H - That attacker-controlled event_file is passed to event_hist_trigger_parse(\"!hist\"), which list_del_rcu()s file->triggers and runs cmd_ops->free on objects taken from the sprayed hist_trigger_data, a heap write and control-flow primitive.\nA:H - The commit reproduces a KASAN slab-use-after-free in event_hist_trigger_free() when the target hist is removed after the compatible one. Without KASAN, the stale hist_data->event_file dereference oopses or panics the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_hist.c" ], "versions": [ { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "a6165126b1a1b26342b55be6eb6ee23af8756aba", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "173914501b97236d7ea7dc2af7f30feddd4e1436", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "ac815a379644b2ad5008a009a3516ada31b5dd82", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "8b307d64a60548e4a74cb746f74d7ed4bd49965e", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "7a111ba0d1b74c99bc8f096565dc71945f694254", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "3609ada3c12cecfb0ae5ee82ef4f86c5f18a2dea", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "9631dbccd3c649b567a5aafffea6b00634183997", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "7cafc82e6153f05a221be678cd649d02e06ba909", "status": "affected", "versionType": "git" }, { "version": "02205a6752f223779a1b0e9e8ffacbea6e717851", "lessThan": "d5c42664fc094899af9aae5300b27fe8fdb658ef", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/trace/trace_events_hist.c" ], "versions": [ { "version": "4.17", "status": "affected" }, { "version": "0", "lessThan": "4.17", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.273", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.60", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.14", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3.1", "lessThanOrEqual": "7.3.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.4-rc1", "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": "4.17", "versionEndExcluding": "5.10.273" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "5.15.224" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.1.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.6.161" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.12.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.18.60" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.2.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.3.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.4-rc1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a6165126b1a1b26342b55be6eb6ee23af8756aba" }, { "url": "https://git.kernel.org/stable/c/173914501b97236d7ea7dc2af7f30feddd4e1436" }, { "url": "https://git.kernel.org/stable/c/ac815a379644b2ad5008a009a3516ada31b5dd82" }, { "url": "https://git.kernel.org/stable/c/8b307d64a60548e4a74cb746f74d7ed4bd49965e" }, { "url": "https://git.kernel.org/stable/c/7a111ba0d1b74c99bc8f096565dc71945f694254" }, { "url": "https://git.kernel.org/stable/c/3609ada3c12cecfb0ae5ee82ef4f86c5f18a2dea" }, { "url": "https://git.kernel.org/stable/c/9631dbccd3c649b567a5aafffea6b00634183997" }, { "url": "https://git.kernel.org/stable/c/7cafc82e6153f05a221be678cd649d02e06ba909" }, { "url": "https://git.kernel.org/stable/c/d5c42664fc094899af9aae5300b27fe8fdb658ef" } ], "title": "tracing: Save the event file instead of the compatible histogram", "x_generator": { "engine": "bippy-1.2.0" } } } }