dm cache: fix out-of-bounds access to the dirty bitset when resizing
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: dm cache: fix out-of-bounds access to the dirty bitset when resizing dm-cache checks the dirty bits of the cache blocks to be dropped when shrinking the fast device, but an index bug in bitset iteration causes out-of-bounds access. Reproduce steps: 1. create a cache device of 1024 cache blocks (128 bytes dirty bitset) dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. shrink the fast device to 512 cache blocks, triggering out-of-bounds access to the dirty bitset (offset 0x80) dmsetup suspend cache dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0 Read of size 8 at addr ffffc900000f3080 by task dmsetup/131 (...snip...) The buggy address belongs to the virtual mapping at [ffffc900000f3000, ffffc900000f5000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by making the index post-incremented.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.13 and later | 4.19.324, 5.4.286, 5.10.230, 5.15.172, 6.1.117, 6.6.61, 6.11.8, 6.12 | Patch available | CNA |
- Linux VendorLinux Affected 3.13 and later Fixed in 4.19.324, 5.4.286, 5.10.230, 5.15.172, 6.1.117, 6.6.61, 6.11.8, 6.12 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 3.13 to before 4.19.324; 4.20 to before 5.4.286; 5.5 to before 5.10.230; 5.11 to before 5.15.172; 5.16 to before 6.1.117; 6.2 to before 6.6.61; 6.7 to before 6.11.8 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* | 6.12 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* | 6.12 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* | 6.12 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:* | 6.12 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:* | 6.12 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc6:*:*:*:*:*:* | 6.12 rc6 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.13 to before 4.19.324; 4.20 to before 5.4.286; 5.5 to before 5.10.230; 5.11 to before 5.15.172; 5.16 to before 6.1.117; 6.2 to before 6.6.61; 6.7 to before 6.11.8 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* Versions 6.12 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* Versions 6.12 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* Versions 6.12 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:* Versions 6.12 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:* Versions 6.12 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc6:*:*:*:*:*:* Versions 6.12 rc6 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.19.324, 5.4.286, 5.10.230, 5.15.172, 6.1.117, 6.6.61, 6.11.8, 6.12
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Timeline
- 2026-10-02 Threatist record created from CVE-2024-50279
- 2026-10-03 Alias added: GHSA-v6rg-qv6j-p6gp
References
Patch 8
- https://git.kernel.org/stable/c/4fa4feb873cea0e9d6ff883b37cca6f33169d8b4
- https://git.kernel.org/stable/c/8501e38dc9e0060814c4085815fc83da3e6d43bf
- https://git.kernel.org/stable/c/ee1f74925717ab36f6a091104c170639501ce818
- https://git.kernel.org/stable/c/ff1dd8a04c30e8d4e2fd5c83198ca672eb6a9e7f
- https://git.kernel.org/stable/c/56507203e1b6127967ec2b51fb0b23a0d4af1334
- https://git.kernel.org/stable/c/e57648ce325fa405fe6bbd0e6a618ced7c301a2d
- https://git.kernel.org/stable/c/3b02c40ff10fdf83cc545850db208de855ebe22c
- https://git.kernel.org/stable/c/792227719725497ce10a8039803bec13f89f8910
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Sources
- CVE-2024-50279 · CVE Program
- CVE-2024-50279 · NVD
- FIRST EPSS
- GHSA-v6rg-qv6j-p6gp · GitHub Advisory Database · CC BY 4.0
- CVE-2024-50279 · Red Hat security data · CC BY 4.0
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