Linux: Use After Free
CVE-2024-46740 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 5a32bfd23022ffa7e152f273fa3fa29befb7d929, 3a8154bb4ab4a01390a3abf1e6afac296e037da4, eef79854a04feac5b861f94d7b19cbbe79874117 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 5a32bfd23022ffa7e152f273fa3fa29befb7d929 or 3a8154bb4ab4a01390a3abf1e6afac296e037da4 or eef79854a04feac5b861f94d7b19cbbe79874117 or 4f79e0b80dc69bd5eaaed70f0df1b558728b4e59, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.284 or 5.10.226 or 5.15.167 or 6.1.110, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | c056a6ba35e00ae943e377eb09abd77a6915b31a up to, but not including, 5a32bfd23022ffa7e152f273fa3fa29befb7d929; 23e9d815fad84c1bee3742a8de4bd39510435362 up to, but not including, 3a8154bb4ab4a01390a3abf1e6afac296e037da4; 7a9ad4aceb0226b391c9d3b8e4ac2e7d438b6bde up to, but not including, eef79854a04feac5b861f94d7b19cbbe79874117; 6d98eb95b450a75adb4516a1d33652dc78d2b20c up to, but not including, 4f79e0b80dc69bd5eaaed70f0df1b558728b4e59; 6d98eb95b450a75adb4516a1d33652dc78d2b20c up to, but not including, 1f33d9f1d9ac3f0129f8508925000900c2fe5bb0; 6d98eb95b450a75adb4516a1d33652dc78d2b20c up to, but not including, 109e845c1184c9f786d41516348ba3efd9112792; 6d98eb95b450a75adb4516a1d33652dc78d2b20c up to, but not including, 4df153652cc46545722879415937582028c18af5; 66e12f5b3a9733f941893a00753b10498724607d; and 5 more ranges | 5a32bfd23022ffa7e152f273fa3fa29befb7d929, 3a8154bb4ab4a01390a3abf1e6afac296e037da4, eef79854a04feac5b861f94d7b19cbbe79874117, 4f79e0b80dc69bd5eaaed70f0df1b558728b4e59, 1f33d9f1d9ac3f0129f8508925000900c2fe5bb0, 109e845c1184c9f786d41516348ba3efd9112792 |
| Linux | Linux Kernel | 5.4.226 up to, but not including, 5.4.284; 5.10.157 up to, but not including, 5.10.226; 5.15.17 up to, but not including, 5.15.167; 5.17 up to, but not including, 6.1.110; 6.2 up to, but not including, 6.6.51; 6.7 up to, but not including, 6.10.10; 6.11 | 5.4.284, 5.10.226, 5.15.167, 6.1.110, 6.6.51, 6.10.10 |
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 | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: binder: fix UAF caused by offsets overwrite Binder objects are processed and copied individually into the target buffer during transactions. Any raw data in-between these objects is copied as well. However, this raw data copy lacks an out-of-bounds check. If the raw data exceeds the data section size then the copy overwrites the offsets section. This eventually triggers an error that attempts to unwind the processed objects. However, at this point the offsets used to index these objects are now corrupted. Unwinding with corrupted offsets can result in decrements of arbitrary nodes and lead to their premature release. Other users of such nodes are left with a dangling pointer triggering a use-after-free. This issue is made evident by the following KASAN report (trimmed): ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c Write of size 4 at addr ffff47fc91598f04 by task binder-util/743 CPU: 9 UID: 0 PID: 743 Comm: binder-util Not tainted 6.11.0-rc4 #1 Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x19c binder_free_buf+0x128/0x434 binder_thread_write+0x8a4/0x3260 binder_ioctl+0x18f0/0x258c [...] Allocated by task 743: __kmalloc_cache_noprof+0x110/0x270 binder_new_node+0x50/0x700 binder_transaction+0x413c/0x6da8 binder_thread_write+0x978/0x3260 binder_ioctl+0x18f0/0x258c [...] Freed by task 745: kfree+0xbc/0x208 binder_thread_read+0x1c5c/0x37d4 binder_ioctl+0x16d8/0x258c [...] ================================================================== To avoid this issue, let's check that the raw data copy is within the boundaries of the data section.
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/109e845c1184c9f786d41516348ba3efd9112792
- git.kernel.org/stable/c/1f33d9f1d9ac3f0129f8508925000900c2fe5bb0
- git.kernel.org/stable/c/3a8154bb4ab4a01390a3abf1e6afac296e037da4
- git.kernel.org/stable/c/4df153652cc46545722879415937582028c18af5
- git.kernel.org/stable/c/4f79e0b80dc69bd5eaaed70f0df1b558728b4e59
- git.kernel.org/stable/c/5a32bfd23022ffa7e152f273fa3fa29befb7d929
- git.kernel.org/stable/c/eef79854a04feac5b861f94d7b19cbbe79874117
Other references
Recent Use After Free vulnerabilities
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