Linux: Use After Free
CVE-2023-53640 is a high-severity use after free 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 8f1512d78b5de928f4616a871e77b58fd546e651, 8d81d3b0ed3610d24191d24f8e9e20f6775f0cc5, f5e61e3fe799ba2fda4320af23d26d28c3302045 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 8f1512d78b5de928f4616a871e77b58fd546e651 or 8d81d3b0ed3610d24191d24f8e9e20f6775f0cc5 or f5e61e3fe799ba2fda4320af23d26d28c3302045 or 75e5fab7db0cecb6e16b22c34608f0b40a4c7cd1, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.114 or 6.1.31 or 6.3.5, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | c39667ddcfc516fee084e449179d54430a558298 up to, but not including, 8f1512d78b5de928f4616a871e77b58fd546e651; c39667ddcfc516fee084e449179d54430a558298 up to, but not including, 8d81d3b0ed3610d24191d24f8e9e20f6775f0cc5; c39667ddcfc516fee084e449179d54430a558298 up to, but not including, f5e61e3fe799ba2fda4320af23d26d28c3302045; c39667ddcfc516fee084e449179d54430a558298 up to, but not including, 75e5fab7db0cecb6e16b22c34608f0b40a4c7cd1; 5.12 | 8f1512d78b5de928f4616a871e77b58fd546e651, 8d81d3b0ed3610d24191d24f8e9e20f6775f0cc5, f5e61e3fe799ba2fda4320af23d26d28c3302045, 75e5fab7db0cecb6e16b22c34608f0b40a4c7cd1 |
| Linux | Linux Kernel | 5.12 up to, but not including, 5.15.114; 5.16 up to, but not including, 6.1.31; 6.2 up to, but not including, 6.3.5; 6.4 | 5.15.114, 6.1.31, 6.3.5 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.3 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: ASoC: lpass: Fix for KASAN use_after_free out of bounds When we run syzkaller we get below Out of Bounds error. "KASAN: slab-out-of-bounds Read in regcache_flat_read" Below is the backtrace of the issue: BUG: KASAN: slab-out-of-bounds in regcache_flat_read+0x10c/0x110 Read of size 4 at addr ffffff8088fbf714 by task syz-executor.4/14144 CPU: 6 PID: 14144 Comm: syz-executor.4 Tainted: G W Hardware name: Qualcomm Technologies, Inc. sc7280 CRD platform (rev5+) (DT) Call trace: dump_backtrace+0x0/0x4ec show_stack+0x34/0x50 dump_stack_lvl+0xdc/0x11c print_address_description+0x30/0x2d8 kasan_report+0x178/0x1e4 __asan_report_load4_noabort+0x44/0x50 regcache_flat_read+0x10c/0x110 regcache_read+0xf8/0x5a0 _regmap_read+0x45c/0x86c _regmap_update_bits+0x128/0x290 regmap_update_bits_base+0xc0/0x15c snd_soc_component_update_bits+0xa8/0x22c snd_soc_component_write_field+0x68/0xd4 tx_macro_put_dec_enum+0x1d0/0x268 snd_ctl_elem_write+0x288/0x474 By Error checking and checking valid values issue gets rectifies.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free 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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