Linux: Out-of-bounds Write
CVE-2022-50258 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 89243a7b0ea19606ba1c2873c9d569026ccb344f, d481fd6064bf215d7c5068e15aa390c3b16c9cd0, 17dbe90e13f52848c460d253f15b765038ec6dc0 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 0.17% 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 89243a7b0ea19606ba1c2873c9d569026ccb344f or d481fd6064bf215d7c5068e15aa390c3b16c9cd0 or 17dbe90e13f52848c460d253f15b765038ec6dc0 or d6ef66194bb4a6c18f5b9649bf62597909b040e4, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.308 or 4.19.276 or 5.4.235 or 5.10.173, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, 89243a7b0ea19606ba1c2873c9d569026ccb344f; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, d481fd6064bf215d7c5068e15aa390c3b16c9cd0; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, 17dbe90e13f52848c460d253f15b765038ec6dc0; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, d6ef66194bb4a6c18f5b9649bf62597909b040e4; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, 3a3a5e3f94068cd562d62a57da6983c8cd07d53c; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, 881f50d76c3892262730ddf5c894eb00310e736c; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, ba166e0ebdde3dfa833f0a3edaf2b2934d4a87f7; 0af29bf7c1ddf5f3c35577409de46ede5e8d7845 up to, but not including, 0a06cadcc2a0044e4a117cc0e61436fc3a0dad69; and 1 more ranges | 89243a7b0ea19606ba1c2873c9d569026ccb344f, d481fd6064bf215d7c5068e15aa390c3b16c9cd0, 17dbe90e13f52848c460d253f15b765038ec6dc0, d6ef66194bb4a6c18f5b9649bf62597909b040e4, 3a3a5e3f94068cd562d62a57da6983c8cd07d53c, 881f50d76c3892262730ddf5c894eb00310e736c |
| Linux | Linux Kernel | before 4.14.308; 4.15 up to, but not including, 4.19.276; 4.20 up to, but not including, 5.4.235; 5.5 up to, but not including, 5.10.173; 5.11 up to, but not including, 5.15.99; 5.16 up to, but not including, 6.1.16; 6.2 up to, but not including, 6.2.3 | 4.14.308, 4.19.276, 5.4.235, 5.10.173, 5.15.99, 6.1.16 |
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
- HighData or code can be modified at will.
- 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:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: Fix potential stack-out-of-bounds in brcmf_c_preinit_dcmds() This patch fixes a stack-out-of-bounds read in brcmfmac that occurs when 'buf' that is not null-terminated is passed as an argument of strsep() in brcmf_c_preinit_dcmds(). This buffer is filled with a firmware version string by memcpy() in brcmf_fil_iovar_data_get(). The patch ensures buf is null-terminated. Found by a modified version of syzkaller. [ 47.569679][ T1897] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43236b for chip BCM43236/3 [ 47.582839][ T1897] brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available [ 47.601565][ T1897] ================================================================== [ 47.602574][ T1897] BUG: KASAN: stack-out-of-bounds in strsep+0x1b2/0x1f0 [ 47.603447][ T1897] Read of size 1 at addr ffffc90001f6f000 by task kworker/0:2/1897 [ 47.604336][ T1897] [ 47.604621][ T1897] CPU: 0 PID: 1897 Comm: kworker/0:2 Tainted: G O 5.14.0+ #131 [ 47.605617][ T1897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 [ 47.606907][ T1897] Workqueue: usb_hub_wq hub_event [ 47.607453][ T1897] Call Trace: [ 47.607801][ T1897] dump_stack_lvl+0x8e/0xd1 [ 47.608295][ T1897] print_address_description.constprop.0.cold+0xf/0x334 [ 47.609009][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609434][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609863][ T1897] kasan_report.cold+0x83/0xdf [ 47.610366][ T1897] ? strsep+0x1b2/0x1f0 [ 47.610882][ T1897] strsep+0x1b2/0x1f0 [ 47.611300][ T1897] ? brcmf_fil_iovar_data_get+0x3a/0xf0 [ 47.611883][ T1897] brcmf_c_preinit_dcmds+0x995/0xc40 [ 47.612434][ T1897] ? brcmf_c_set_joinpref_default+0x100/0x100 [ 47.613078][ T1897] ? rcu_read_lock_sched_held+0xa1/0xd0 [ 47.613662][ T1897] ? rcu_read_lock_bh_held+0xb0/0xb0 [ 47.614208][ T1897] ? lock_acquire+0x19d/0x4e0 [ 47.614704][ T1897] ? find_held_lock+0x2d/0x110 [ 47.615236][ T1897] ? brcmf_usb_deq+0x1a7/0x260 [ 47.615741][ T1897] ? brcmf_usb_rx_fill_all+0x5a/0xf0 [ 47.616288][ T1897] brcmf_attach+0x246/0xd40 [ 47.616758][ T1897] ? wiphy_new_nm+0x1703/0x1dd0 [ 47.617280][ T1897] ? kmemdup+0x43/0x50 [ 47.617720][ T1897] brcmf_usb_probe+0x12de/0x1690 [ 47.618244][ T1897] ? brcmf_usbdev_qinit.constprop.0+0x470/0x470 [ 47.618901][ T1897] usb_probe_interface+0x2aa/0x760 [ 47.619429][ T1897] ? usb_probe_device+0x250/0x250 [ 47.619950][ T1897] really_probe+0x205/0xb70 [ 47.620435][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.621048][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.621595][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.622209][ T1897] driver_probe_device+0x4e/0x150 [ 47.622739][ T1897] __device_attach_driver+0x1cc/0x2a0 [ 47.623287][ T1897] bus_for_each_drv+0x156/0x1d0 [ 47.623796][ T1897] ? bus_rescan_devices+0x30/0x30 [ 47.624309][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.624907][ T1897] ? trace_hardirqs_on+0x46/0x160 [ 47.625437][ T1897] __device_attach+0x23f/0x3a0 [ 47.625924][ T1897] ? device_bind_driver+0xd0/0xd0 [ 47.626433][ T1897] ? kobject_uevent_env+0x287/0x14b0 [ 47.627057][ T1897] bus_probe_device+0x1da/0x290 [ 47.627557][ T1897] device_add+0xb7b/0x1eb0 [ 47.628027][ T1897] ? wait_for_completion+0x290/0x290 [ 47.628593][ T1897] ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 [ 47.629249][ T1897] usb_set_configuration+0xf59/0x16f0 [ 47.629829][ T1897] usb_generic_driver_probe+0x82/0xa0 [ 47.630385][ T1897] usb_probe_device+0xbb/0x250 [ 47.630927][ T1897] ? usb_suspend+0x590/0x590 [ 47.631397][ T1897] really_probe+0x205/0xb70 [ 47.631855][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.632469][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.633002][ ---truncated---
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
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/0a06cadcc2a0044e4a117cc0e61436fc3a0dad69
- git.kernel.org/stable/c/17dbe90e13f52848c460d253f15b765038ec6dc0
- git.kernel.org/stable/c/3a3a5e3f94068cd562d62a57da6983c8cd07d53c
- git.kernel.org/stable/c/881f50d76c3892262730ddf5c894eb00310e736c
- git.kernel.org/stable/c/89243a7b0ea19606ba1c2873c9d569026ccb344f
- git.kernel.org/stable/c/ba166e0ebdde3dfa833f0a3edaf2b2934d4a87f7
- git.kernel.org/stable/c/d481fd6064bf215d7c5068e15aa390c3b16c9cd0
- git.kernel.org/stable/c/d6ef66194bb4a6c18f5b9649bf62597909b040e4
Recent Out-of-bounds Write vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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