Linux: Use After Free
CVE-2024-50127 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 2f868ce6013548a713c431c679ef73747a66fcf3, 8a283a19026aaae8a773fd8061263cfa315b127f, 999612996df28d81f163dad530d7f8026e03aec6 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 0.25% 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 2f868ce6013548a713c431c679ef73747a66fcf3 or 8a283a19026aaae8a773fd8061263cfa315b127f or 999612996df28d81f163dad530d7f8026e03aec6 or fe371f084073e8672a2d7d46b335c3c060d1e301, whichever matches your release line, or a later version.
- Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1.1 or a later version.
- Update Linux Kernel to 5.15.170 or 6.1.115 or 6.6.59 or 6.11.6, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, 2f868ce6013548a713c431c679ef73747a66fcf3; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, 8a283a19026aaae8a773fd8061263cfa315b127f; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, 999612996df28d81f163dad530d7f8026e03aec6; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, fe371f084073e8672a2d7d46b335c3c060d1e301; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, 0d4c0d2844e4eac3aed647f948fd7e60eea56a61; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, 2240f9376f20f8b6463232b4ca7292569217237f; a3d43c0d56f1b94e74963a2fbadfb70126d92213 up to, but not including, f504465970aebb2467da548f7c1efbbf36d0f44b; 5.2 | 2f868ce6013548a713c431c679ef73747a66fcf3, 8a283a19026aaae8a773fd8061263cfa315b127f, 999612996df28d81f163dad530d7f8026e03aec6, fe371f084073e8672a2d7d46b335c3c060d1e301, 0d4c0d2844e4eac3aed647f948fd7e60eea56a61, 2240f9376f20f8b6463232b4ca7292569217237f |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1.1 | V1.1.1 |
| Linux | Linux Kernel | 5.2 up to, but not including, 5.15.170; 5.16 up to, but not including, 6.1.115; 6.2 up to, but not including, 6.6.59; 6.7 up to, but not including, 6.11.6; 6.12 | 5.15.170, 6.1.115, 6.6.59, 6.11.6 |
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 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: net: sched: fix use-after-free in taprio_change() In 'taprio_change()', 'admin' pointer may become dangling due to sched switch / removal caused by 'advance_sched()', and critical section protected by 'q->current_entry_lock' is too small to prevent from such a scenario (which causes use-after-free detected by KASAN). Fix this by prefer 'rcu_replace_pointer()' over 'rcu_assign_pointer()' to update 'admin' immediately before an attempt to schedule freeing.
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/0d4c0d2844e4eac3aed647f948fd7e60eea56a61
- git.kernel.org/stable/c/2240f9376f20f8b6463232b4ca7292569217237f
- git.kernel.org/stable/c/2f868ce6013548a713c431c679ef73747a66fcf3
- git.kernel.org/stable/c/8a283a19026aaae8a773fd8061263cfa315b127f
- git.kernel.org/stable/c/999612996df28d81f163dad530d7f8026e03aec6
- git.kernel.org/stable/c/f504465970aebb2467da548f7c1efbbf36d0f44b
- git.kernel.org/stable/c/fe371f084073e8672a2d7d46b335c3c060d1e301
Other references
Recent Use After Free vulnerabilities
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