Linux: Use After Free
CVE-2023-52974 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 496af9d3682ed4c28fb734342a09e6cc0c056ea4, 6abd4698f4c8a78e7bbfc421205c060c199554a0, d4d765f4761f9e3a2d62992f825aeee593bcb6b9 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 0.29% 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 496af9d3682ed4c28fb734342a09e6cc0c056ea4 or 6abd4698f4c8a78e7bbfc421205c060c199554a0 or d4d765f4761f9e3a2d62992f825aeee593bcb6b9 or 9758ffe1c07b86aefd7ca8e40d9a461293427ca0, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.306 or 4.19.273 or 5.4.232 or 5.10.168, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, 496af9d3682ed4c28fb734342a09e6cc0c056ea4; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, 6abd4698f4c8a78e7bbfc421205c060c199554a0; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, d4d765f4761f9e3a2d62992f825aeee593bcb6b9; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, 9758ffe1c07b86aefd7ca8e40d9a461293427ca0; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, 0aaabdb900c7415caa2006ef580322f7eac5f6b6; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, 61e43ebfd243bcbad11be26bd921723027b77441; a79af8a64d395bd89de8695a5ea5e1a7f01f02a8 up to, but not including, f484a794e4ee2a9ce61f52a78e810ac45f3fe3b3; 2.6.39 | 496af9d3682ed4c28fb734342a09e6cc0c056ea4, 6abd4698f4c8a78e7bbfc421205c060c199554a0, d4d765f4761f9e3a2d62992f825aeee593bcb6b9, 9758ffe1c07b86aefd7ca8e40d9a461293427ca0, 0aaabdb900c7415caa2006ef580322f7eac5f6b6, 61e43ebfd243bcbad11be26bd921723027b77441 |
| Linux | Linux Kernel | before 4.14.306; 4.15 up to, but not including, 4.19.273; 4.20 up to, but not including, 5.4.232; 5.5 up to, but not including, 5.10.168; 5.11 up to, but not including, 5.15.93; 5.16 up to, but not including, 6.1.11; 6.2 | 4.14.306, 4.19.273, 5.4.232, 5.10.168, 5.15.93, 6.1.11 |
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 CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: scsi: iscsi_tcp: Fix UAF during login when accessing the shost ipaddress If during iscsi_sw_tcp_session_create() iscsi_tcp_r2tpool_alloc() fails, userspace could be accessing the host's ipaddress attr. If we then free the session via iscsi_session_teardown() while userspace is still accessing the session we will hit a use after free bug. Set the tcp_sw_host->session after we have completed session creation and can no longer fail.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0aaabdb900c7415caa2006ef580322f7eac5f6b6
- git.kernel.org/stable/c/496af9d3682ed4c28fb734342a09e6cc0c056ea4
- git.kernel.org/stable/c/61e43ebfd243bcbad11be26bd921723027b77441
- git.kernel.org/stable/c/6abd4698f4c8a78e7bbfc421205c060c199554a0
- git.kernel.org/stable/c/9758ffe1c07b86aefd7ca8e40d9a461293427ca0
- git.kernel.org/stable/c/d4d765f4761f9e3a2d62992f825aeee593bcb6b9
- git.kernel.org/stable/c/f484a794e4ee2a9ce61f52a78e810ac45f3fe3b3
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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