{"id":"CVE-2024-27399","url":"https://www.cyber-defence.io/tools/cve/CVE-2024-27399","generatedAt":"2026-10-28T01:13:37.512Z","title":"In the Linux kernel, the following vulnerability has been resolved: Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout There is a race condition between l2cap_chan_timeout() and l2cap_chan_del().","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout\n\nThere is a race condition between l2cap_chan_timeout() and\nl2cap_chan_del(). When we use l2cap_chan_del() to delete the\nchannel, the chan->conn will be set to null. But the conn could\nbe dereferenced again in the mutex_lock() of l2cap_chan_timeout().\nAs a result the null pointer dereference bug will happen. The\nKASAN report triggered by POC is shown below:\n\n[  472.074580] ==================================================================\n[  472.075284] BUG: KASAN: null-ptr-deref in mutex_lock+0x68/0xc0\n[  472.075308] Write of size 8 at addr 0000000000000158 by task kworker/0:0/7\n[  472.075308]\n[  472.075308] CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.9.0-rc5-00356-g78c0094a146b #36\n[  472.075308] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4\n[  472.075308] Workqueue: events l2cap_chan_timeout\n[  472.075308] Call Trace:\n[  472.075308]  <TASK>\n[  472.075308]  dump_stack_lvl+0x137/0x1a0\n[  472.075308]  print_report+0x101/0x250\n[  472.075308]  ? __virt_addr_valid+0x77/0x160\n[  472.075308]  ? mutex_lock+0x68/0xc0\n[  472.075308]  kasan_report+0x139/0x170\n[  472.075308]  ? mutex_lock+0x68/0xc0\n[  472.075308]  kasan_check_range+0x2c3/0x2e0\n[  472.075308]  mutex_lock+0x68/0xc0\n[  472.075308]  l2cap_chan_timeout+0x181/0x300\n[  472.075308]  process_one_work+0x5d2/0xe00\n[  472.075308]  worker_thread+0xe1d/0x1660\n[  472.075308]  ? pr_cont_work+0x5e0/0x5e0\n[  472.075308]  kthread+0x2b7/0x350\n[  472.075308]  ? pr_cont_work+0x5e0/0x5e0\n[  472.075308]  ? kthread_blkcg+0xd0/0xd0\n[  472.075308]  ret_from_fork+0x4d/0x80\n[  472.075308]  ? kthread_blkcg+0xd0/0xd0\n[  472.075308]  ret_from_fork_asm+0x11/0x20\n[  472.075308]  </TASK>\n[  472.075308] ==================================================================\n[  472.094860] Disabling lock debugging due to kernel taint\n[  472.096136] BUG: kernel NULL pointer dereference, address: 0000000000000158\n[  472.096136] #PF: supervisor write access in kernel mode\n[  472.096136] #PF: error_code(0x0002) - not-present page\n[  472.096136] PGD 0 P4D 0\n[  472.096136] Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI\n[  472.096136] CPU: 0 PID: 7 Comm: kworker/0:0 Tainted: G    B              6.9.0-rc5-00356-g78c0094a146b #36\n[  472.096136] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4\n[  472.096136] Workqueue: events l2cap_chan_timeout\n[  472.096136] RIP: 0010:mutex_lock+0x88/0xc0\n[  472.096136] Code: be 08 00 00 00 e8 f8 23 1f fd 4c 89 f7 be 08 00 00 00 e8 eb 23 1f fd 42 80 3c 23 00 74 08 48 88\n[  472.096136] RSP: 0018:ffff88800744fc78 EFLAGS: 00000246\n[  472.096136] RAX: 0000000000000000 RBX: 1ffff11000e89f8f RCX: ffffffff8457c865\n[  472.096136] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88800744fc78\n[  472.096136] RBP: 0000000000000158 R08: ffff88800744fc7f R09: 1ffff11000e89f8f\n[  472.096136] R10: dffffc0000000000 R11: ffffed1000e89f90 R12: dffffc0000000000\n[  472.096136] R13: 0000000000000158 R14: ffff88800744fc78 R15: ffff888007405a00\n[  472.096136] FS:  0000000000000000(0000) GS:ffff88806d200000(0000) knlGS:0000000000000000\n[  472.096136] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  472.096136] CR2: 0000000000000158 CR3: 000000000da32000 CR4: 00000000000006f0\n[  472.096136] Call Trace:\n[  472.096136]  <TASK>\n[  472.096136]  ? __die_body+0x8d/0xe0\n[  472.096136]  ? page_fault_oops+0x6b8/0x9a0\n[  472.096136]  ? kernelmode_fixup_or_oops+0x20c/0x2a0\n[  472.096136]  ? do_user_addr_fault+0x1027/0x1340\n[  472.096136]  ? _printk+0x7a/0xa0\n[  472.096136]  ? mutex_lock+0x68/0xc0\n[  472.096136]  ? add_taint+0x42/0xd0\n[  472.096136]  ? exc_page_fault+0x6a/0x1b0\n[  472.096136]  ? asm_exc_page_fault+0x26/0x30\n[  472.096136]  ? mutex_lock+0x75/0xc0\n[  472.096136]  ? mutex_lock+0x88/0xc0\n[  472.096136]  ? mutex_lock+0x75/0xc0\n[  472.096136]  l2cap_chan_timeo\n---truncated---","published":"2024-05-14T15:12:29.000Z","lastModified":"2026-06-17T07:19:49.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["linux/linux kernel","debian/debian linux","fedoraproject/fedora"],"epss":{"score":0.00304,"percentile":0.2296,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.30%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/06acb75e7ed600d0bbf7bff5628aa8f24a97978c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6466ee65e5b27161c846c73ef407f49dfa1bd1d9","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8960ff650aec70485b40771cd8e6e8c4cb467d33","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/955b5b6c54d95b5e7444dfc81c95c8e013f27ac0","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/adf0398cee86643b8eacde95f17d073d022f782c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e137e2ba96e51902dc2878131823a96bf8e638ae","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e97e16433eb4533083b096a3824b93a5ca3aee79","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/eb86f955488c39526534211f2610e48a5cf8ead4","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/06acb75e7ed600d0bbf7bff5628aa8f24a97978c","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/6466ee65e5b27161c846c73ef407f49dfa1bd1d9","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/8960ff650aec70485b40771cd8e6e8c4cb467d33","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/955b5b6c54d95b5e7444dfc81c95c8e013f27ac0","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/adf0398cee86643b8eacde95f17d073d022f782c","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/e137e2ba96e51902dc2878131823a96bf8e638ae","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/e97e16433eb4533083b096a3824b93a5ca3aee79","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/eb86f955488c39526534211f2610e48a5cf8ead4","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00019.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DW2MIOIMOFUSNLHLRYX23AFR36BMKD65/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OTB4HWU2PTVW5NEYHHLOCXDKG3PYA534/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20240926-0001/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-27399","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}