{"id":"CVE-2025-39683","title":"tracing: Limit access to parser->buffer when trace_get_user failed","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Limit access to parser->buffer when trace_get_user failed\n\nWhen the length of the string written to set_ftrace_filter exceeds\nFTRACE_BUFF_MAX, the following KA…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 634684d79733124f7470b226b0f42aada4426b07 < b842ef39c2ad6156c13afdec25ecc6792a9b67b9","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 41b838420457802f21918df66764b6fbf829d330","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 418b448e1d7470da9d4d4797f71782595ee69c49","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 58ff8064cb4c7eddac4da1a59da039ead586950a","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < d0c68045b8b0f3737ed7bd6b8c83b7887014adee","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 3079517a5ba80901fe828a06998da64b9b8749be","Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 6a909ea83f226803ea0e718f6e88613df9234d58","Linux 24cd31752f47699b89b4b3471155c8e599a1a23a","Linux e9cb474de7ff7a970c2a3951c12ec7e3113c0c35","Linux 6ab671191f64b0da7d547e2ad4dc199ca7e5b558","Linux 3d9281a4ac7171c808f9507f0937eb236b353905","Linux 0b641b25870f02e2423e494365fc5243cc1e2759","Linux ffd51dbfd2900e50c71b5c069fe407957e52d61f","Linux cdd107d7f18158d966c2bc136204fe826dac445c","Linux >= 5.10.36 < 5.10.241","Linux >= 4.4.269 < 4.5","Linux >= 4.9.269 < 4.10","Linux >= 4.14.233 < 4.15","Linux >= 4.19.191 < 4.20","Linux >= 5.4.118 < 5.5","Linux >= 5.11.20 < 5.12","Linux >= 5.12.3 < 5.13","Linux 5.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:53:16.510449Z"},"published":"2025-09-05","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:02:30.066Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39683","references":[{"url":"https://git.kernel.org/stable/c/b842ef39c2ad6156c13afdec25ecc6792a9b67b9"},{"url":"https://git.kernel.org/stable/c/41b838420457802f21918df66764b6fbf829d330"},{"url":"https://git.kernel.org/stable/c/418b448e1d7470da9d4d4797f71782595ee69c49"},{"url":"https://git.kernel.org/stable/c/58ff8064cb4c7eddac4da1a59da039ead586950a"},{"url":"https://git.kernel.org/stable/c/d0c68045b8b0f3737ed7bd6b8c83b7887014adee"},{"url":"https://git.kernel.org/stable/c/3079517a5ba80901fe828a06998da64b9b8749be"},{"url":"https://git.kernel.org/stable/c/6a909ea83f226803ea0e718f6e88613df9234d58"}],"tags":["cve.org"],"epss":0.00184,"epssPercentile":0.07952,"ingestedAt":"2026-10-15T05:52:46.080Z","slug":"CVE-2025-39683","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Limit access to parser->buffer when trace_get_user failed\n\nWhen the length of the string written to set_ftrace_filter exceeds\nFTRACE_BUFF_MAX, the following KASAN alarm will be triggered:\n\nBUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0\nRead of size 1 at addr ffff0000d00bd5ba by task ash/165\n\nCPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty\nHardware name: linux,dummy-virt (DT)\nCall trace:\n show_stack+0x34/0x50 (C)\n dump_stack_lvl+0xa0/0x158\n print_address_description.constprop.0+0x88/0x398\n print_report+0xb0/0x280\n kasan_report+0xa4/0xf0\n __asan_report_load1_noabort+0x20/0x30\n strsep+0x18c/0x1b0\n ftrace_process_regex.isra.0+0x100/0x2d8\n ftrace_regex_release+0x484/0x618\n __fput+0x364/0xa58\n ____fput+0x28/0x40\n task_work_run+0x154/0x278\n do_notify_resume+0x1f0/0x220\n el0_svc+0xec/0xf0\n el0t_64_sync_handler+0xa0/0xe8\n el0t_64_sync+0x1ac/0x1b0\n\nThe reason is that trace_get_user will fail when processing a string\nlonger than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0.\nThen an OOB access will be triggered in ftrace_regex_release->\nftrace_process_regex->strsep->strpbrk. We can solve this problem by\nlimiting access to parser->buffer when trace_get_user failed.\n\n## Affected\n\n- `Linux >= 634684d79733124f7470b226b0f42aada4426b07 < b842ef39c2ad6156c13afdec25ecc6792a9b67b9`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 41b838420457802f21918df66764b6fbf829d330`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 418b448e1d7470da9d4d4797f71782595ee69c49`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 58ff8064cb4c7eddac4da1a59da039ead586950a`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < d0c68045b8b0f3737ed7bd6b8c83b7887014adee`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 3079517a5ba80901fe828a06998da64b9b8749be`\n- `Linux >= 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 < 6a909ea83f226803ea0e718f6e88613df9234d58`\n- `Linux 24cd31752f47699b89b4b3471155c8e599a1a23a`\n- `Linux e9cb474de7ff7a970c2a3951c12ec7e3113c0c35`\n- `Linux 6ab671191f64b0da7d547e2ad4dc199ca7e5b558`\n- `Linux 3d9281a4ac7171c808f9507f0937eb236b353905`\n- `Linux 0b641b25870f02e2423e494365fc5243cc1e2759`\n- `Linux ffd51dbfd2900e50c71b5c069fe407957e52d61f`\n- `Linux cdd107d7f18158d966c2bc136204fe826dac445c`\n- `Linux >= 5.10.36 < 5.10.241`\n- `Linux >= 4.4.269 < 4.5`\n- `Linux >= 4.9.269 < 4.10`\n- `Linux >= 4.14.233 < 4.15`\n- `Linux >= 4.19.191 < 4.20`\n- `Linux >= 5.4.118 < 5.5`\n- `Linux >= 5.11.20 < 5.12`\n- `Linux >= 5.12.3 < 5.13`\n- `Linux 5.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}