CVE-2022-49395 um: Fix out-of-bounds read in LDT setup
An out-of-bounds read in the Linux kernel UML LDT setup can cause a crash or leak stack memory.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49395?
CVE-2022-49395 is a high-severity memory corruption vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
um: Fix out-of-bounds read in LDT setup
syscall_stub_data() expects the data_count parameter to be the number of longs, not bytes.
================================================================== BUG: KASAN: stack-out-of-bounds in syscall_stub_data+0x70/0xe0 Read of size 128 at addr 000000006411f6f0 by task swapper/1
CPU: 0 PID: 1 Comm: swapper Not tainted 5.18.0+ #18 Call Trace: show_stack.cold+0x166/0x2a7 __dump_stack+0x3a/0x43 dump_stack_lvl+0x1f/0x27 print_report.cold+0xdb/0xf81 kasan_report+0x119/0x1f0 kasan_check_range+0x3a3/0x440 memcpy+0x52/0x140 syscall_stub_data+0x70/0xe0 write_ldt_entry+0xac/0x190 init_new_ldt+0x515/0x960 init_new_context+0x2c4/0x4d0 mm_init.constprop.0+0x5ed/0x760 mm_alloc+0x118/0x170 0x60033f48 do_one_initcall+0x1d7/0x860 0x60003e7b kernel_init+0x6e/0x3d4 new_thread_handler+0x1e7/0x2c0
The buggy address belongs to stack of task swapper/1 and is located at offset 64 in frame: init_new_ldt+0x0/0x960
This frame has 2 objects: [32, 40) 'addr' [64, 80) 'desc' ==================================================================
Weakness: CWE-125
Which versions are affected by CVE-2022-49395?
It affects 1 product.
Linux distribution packages (40)
bpftool AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-abi-stablelists AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-core AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-cross-headers AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-debug AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-debug-core AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-debug-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-debug-modules AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-debug-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-doc AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-headers AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-modules AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-rt AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-core AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-debug AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-debug-core AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-debug-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-debug-modules AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-debug-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-modules AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-rt-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.56.1.rt7.397.el8_10 |
kernel-tools AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-tools-libs AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-tools-libs-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-zfcpdump AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-zfcpdump-core AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-zfcpdump-devel AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-zfcpdump-modules AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
kernel-zfcpdump-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
perf AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
python3-perf AlmaLinux:8 | All versions | 4.18.0-553.56.1.el8_10 |
bpftool Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.56.1.el8_10 |
bpftool-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.56.1.el8_10 |
kernel Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.56.1.el8_10 |
kernel-abi-stablelists Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.56.1.el8_10 |
kernel-core Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.56.1.el8_10 |
Products include Linux kernel.
How do I fix CVE-2022-49395?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2022-49395 being exploited?
There is no known exploitation of CVE-2022-49395 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as ALSA-2025:8743, ALSA-2025:8744, DEBIAN-CVE-2022-49395, GHSA-pxwr-cc58-gq3m, RHSA-2025:8743, RHSA-2025:8744 and 3 more.