Linux: Out-of-bounds Read
CVE-2022-50103 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 336626564b58071b8980a4e6a31a8f5d92705d9b, 147f66d22f58712dce7ccdd6a1f6cb3ee8042df4, 357f3f0e522a6ce1ce4a571cb780d9861d53bec7 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 336626564b58071b8980a4e6a31a8f5d92705d9b or 147f66d22f58712dce7ccdd6a1f6cb3ee8042df4 or 357f3f0e522a6ce1ce4a571cb780d9861d53bec7 or f56607b44c9896e51678a7e8cdd3a5479f4b4548, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.137 or 5.15.61 or 5.18.18 or 5.19.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7f51412a415d87ea8598d14722fb31e4f5701257 up to, but not including, 336626564b58071b8980a4e6a31a8f5d92705d9b; 7f51412a415d87ea8598d14722fb31e4f5701257 up to, but not including, 147f66d22f58712dce7ccdd6a1f6cb3ee8042df4; 7f51412a415d87ea8598d14722fb31e4f5701257 up to, but not including, 357f3f0e522a6ce1ce4a571cb780d9861d53bec7; 7f51412a415d87ea8598d14722fb31e4f5701257 up to, but not including, f56607b44c9896e51678a7e8cdd3a5479f4b4548; 7f51412a415d87ea8598d14722fb31e4f5701257 up to, but not including, b6e8d40d43ae4dec00c8fea2593eeea3114b8f44; 3.19 | 336626564b58071b8980a4e6a31a8f5d92705d9b, 147f66d22f58712dce7ccdd6a1f6cb3ee8042df4, 357f3f0e522a6ce1ce4a571cb780d9861d53bec7, f56607b44c9896e51678a7e8cdd3a5479f4b4548, b6e8d40d43ae4dec00c8fea2593eeea3114b8f44 |
| Linux | Linux Kernel | 3.19 up to, but not including, 5.10.137; 5.11 up to, but not including, 5.15.61; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.2 | 5.10.137, 5.15.61, 5.18.18, 5.19.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating that the cpuset will just use the effective CPUs of its parent. So cpuset_can_attach() can call task_can_attach() with an empty mask. This can lead to cpumask_any_and() returns nr_cpu_ids causing the call to dl_bw_of() to crash due to percpu value access of an out of bound CPU value. For example: [80468.182258] BUG: unable to handle page fault for address: ffffffff8b6648b0 : [80468.191019] RIP: 0010:dl_cpu_busy+0x30/0x2b0 : [80468.207946] Call Trace: [80468.208947] cpuset_can_attach+0xa0/0x140 [80468.209953] cgroup_migrate_execute+0x8c/0x490 [80468.210931] cgroup_update_dfl_csses+0x254/0x270 [80468.211898] cgroup_subtree_control_write+0x322/0x400 [80468.212854] kernfs_fop_write_iter+0x11c/0x1b0 [80468.213777] new_sync_write+0x11f/0x1b0 [80468.214689] vfs_write+0x1eb/0x280 [80468.215592] ksys_write+0x5f/0xe0 [80468.216463] do_syscall_64+0x5c/0x80 [80468.224287] entry_SYSCALL_64_after_hwframe+0x44/0xae Fix that by using effective_cpus instead. For cgroup v1, effective_cpus is the same as cpus_allowed. For v2, effective_cpus is the real cpumask to be used by tasks within the cpuset anyway. Also update task_can_attach()'s 2nd argument name to cs_effective_cpus to reflect the change. In addition, a check is added to task_can_attach() to guard against the possibility that cpumask_any_and() may return a value >= nr_cpu_ids.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/147f66d22f58712dce7ccdd6a1f6cb3ee8042df4
- git.kernel.org/stable/c/336626564b58071b8980a4e6a31a8f5d92705d9b
- git.kernel.org/stable/c/357f3f0e522a6ce1ce4a571cb780d9861d53bec7
- git.kernel.org/stable/c/b6e8d40d43ae4dec00c8fea2593eeea3114b8f44
- git.kernel.org/stable/c/f56607b44c9896e51678a7e8cdd3a5479f4b4548
Recent Out-of-bounds Read vulnerabilities
- 7.5 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
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