Linux: Out-of-bounds Write
CVE-2024-56548 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 baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8, f57725bcc5816425e25218fdf5fb6923bc578cdf, e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866 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 baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8 or f57725bcc5816425e25218fdf5fb6923bc578cdf or e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866 or 06cbfbb13ac88f4154c2eb4bc4176f9d10139847, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.325 or 5.4.287 or 5.10.231 or 5.15.174, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, f57725bcc5816425e25218fdf5fb6923bc578cdf; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, 06cbfbb13ac88f4154c2eb4bc4176f9d10139847; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, 3d7bda75e1a6239db053c73acde17ca146317824; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, 21900e8478126ff6afe3b66679f676e74d1f8830; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, 2667c9b7b76efcbc7adbfea249892f20c313b0da; 6596528e391ad978a6a120142cba97a1d7324cb6 up to, but not including, bfeecda050aa9376f642d5b2a71c4112cc6c8216; and 4 more ranges | baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8, f57725bcc5816425e25218fdf5fb6923bc578cdf, e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866, 06cbfbb13ac88f4154c2eb4bc4176f9d10139847, 3d7bda75e1a6239db053c73acde17ca146317824, 21900e8478126ff6afe3b66679f676e74d1f8830 |
| Linux | Linux Kernel | 3.0.8 up to, but not including, 4.19.325; 4.20 up to, but not including, 5.4.287; 5.5 up to, but not including, 5.10.231; 5.11 up to, but not including, 5.15.174; 5.16 up to, but not including, 6.1.120; 6.2 up to, but not including, 6.6.64; 6.7 up to, but not including, 6.11.11; 6.12 up to, but not including, 6.12.2 | 4.19.325, 5.4.287, 5.10.231, 5.15.174, 6.1.120, 6.6.64 |
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: hfsplus: don't query the device logical block size multiple times Devices block sizes may change. One of these cases is a loop device by using ioctl LOOP_SET_BLOCK_SIZE. While this may cause other issues like IO being rejected, in the case of hfsplus, it will allocate a block by using that size and potentially write out-of-bounds when hfsplus_read_wrapper calls hfsplus_submit_bio and the latter function reads a different io_size. Using a new min_io_size initally set to sb_min_blocksize works for the purposes of the original fix, since it will be set to the max between HFSPLUS_SECTOR_SIZE and the first seen logical block size. We still use the max between HFSPLUS_SECTOR_SIZE and min_io_size in case the latter is not initialized. Tested by mounting an hfsplus filesystem with loop block sizes 512, 1024 and 4096. The produced KASAN report before the fix looks like this: [ 419.944641] ================================================================== [ 419.945655] BUG: KASAN: slab-use-after-free in hfsplus_read_wrapper+0x659/0xa0a [ 419.946703] Read of size 2 at addr ffff88800721fc00 by task repro/10678 [ 419.947612] [ 419.947846] CPU: 0 UID: 0 PID: 10678 Comm: repro Not tainted 6.12.0-rc5-00008-gdf56e0f2f3ca #84 [ 419.949007] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 [ 419.950035] Call Trace: [ 419.950384] <TASK> [ 419.950676] dump_stack_lvl+0x57/0x78 [ 419.951212] ? hfsplus_read_wrapper+0x659/0xa0a [ 419.951830] print_report+0x14c/0x49e [ 419.952361] ? __virt_addr_valid+0x267/0x278 [ 419.952979] ? kmem_cache_debug_flags+0xc/0x1d [ 419.953561] ? hfsplus_read_wrapper+0x659/0xa0a [ 419.954231] kasan_report+0x89/0xb0 [ 419.954748] ? hfsplus_read_wrapper+0x659/0xa0a [ 419.955367] hfsplus_read_wrapper+0x659/0xa0a [ 419.955948] ? __pfx_hfsplus_read_wrapper+0x10/0x10 [ 419.956618] ? do_raw_spin_unlock+0x59/0x1a9 [ 419.957214] ? _raw_spin_unlock+0x1a/0x2e [ 419.957772] hfsplus_fill_super+0x348/0x1590 [ 419.958355] ? hlock_class+0x4c/0x109 [ 419.958867] ? __pfx_hfsplus_fill_super+0x10/0x10 [ 419.959499] ? __pfx_string+0x10/0x10 [ 419.960006] ? lock_acquire+0x3e2/0x454 [ 419.960532] ? bdev_name.constprop.0+0xce/0x243 [ 419.961129] ? __pfx_bdev_name.constprop.0+0x10/0x10 [ 419.961799] ? pointer+0x3f0/0x62f [ 419.962277] ? __pfx_pointer+0x10/0x10 [ 419.962761] ? vsnprintf+0x6c4/0xfba [ 419.963178] ? __pfx_vsnprintf+0x10/0x10 [ 419.963621] ? setup_bdev_super+0x376/0x3b3 [ 419.964029] ? snprintf+0x9d/0xd2 [ 419.964344] ? __pfx_snprintf+0x10/0x10 [ 419.964675] ? lock_acquired+0x45c/0x5e9 [ 419.965016] ? set_blocksize+0x139/0x1c1 [ 419.965381] ? sb_set_blocksize+0x6d/0xae [ 419.965742] ? __pfx_hfsplus_fill_super+0x10/0x10 [ 419.966179] mount_bdev+0x12f/0x1bf [ 419.966512] ? __pfx_mount_bdev+0x10/0x10 [ 419.966886] ? vfs_parse_fs_string+0xce/0x111 [ 419.967293] ? __pfx_vfs_parse_fs_string+0x10/0x10 [ 419.967702] ? __pfx_hfsplus_mount+0x10/0x10 [ 419.968073] legacy_get_tree+0x104/0x178 [ 419.968414] vfs_get_tree+0x86/0x296 [ 419.968751] path_mount+0xba3/0xd0b [ 419.969157] ? __pfx_path_mount+0x10/0x10 [ 419.969594] ? kmem_cache_free+0x1e2/0x260 [ 419.970311] do_mount+0x99/0xe0 [ 419.970630] ? __pfx_do_mount+0x10/0x10 [ 419.971008] __do_sys_mount+0x199/0x1c9 [ 419.971397] do_syscall_64+0xd0/0x135 [ 419.971761] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 419.972233] RIP: 0033:0x7c3cb812972e [ 419.972564] Code: 48 8b 0d f5 46 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c2 46 0d 00 f7 d8 64 89 01 48 [ 419.974371] RSP: 002b:00007ffe30632548 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5 [ 419.975048] RAX: ffffffffffffffda RBX: 00007ffe306328d8 RCX: 00007c3cb812972e [ 419.975701] RDX: 0000000020000000 RSI: 0000000020000c80 RDI: ---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: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/06cbfbb13ac88f4154c2eb4bc4176f9d10139847
- git.kernel.org/stable/c/1c82587cb57687de3f18ab4b98a8850c789bedcf
- git.kernel.org/stable/c/21900e8478126ff6afe3b66679f676e74d1f8830
- git.kernel.org/stable/c/2667c9b7b76efcbc7adbfea249892f20c313b0da
- git.kernel.org/stable/c/3d7bda75e1a6239db053c73acde17ca146317824
- git.kernel.org/stable/c/baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8
- git.kernel.org/stable/c/bfeecda050aa9376f642d5b2a71c4112cc6c8216
- git.kernel.org/stable/c/e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866
- git.kernel.org/stable/c/f57725bcc5816425e25218fdf5fb6923bc578cdf
Other references
Recent Out-of-bounds Write vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Linux Kernel Out-of-Bounds Access Exploited
- 7.8 High severity
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