cbcvebase.
CVE-2025-37807
published 2025-05-08

CVE-2025-37807: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix kmemleak warning for percpu hashmap Vlad Poenaru reported the following kmemleak…

PriorityP417medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
8.5th percentile
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix kmemleak warning for percpu hashmap Vlad Poenaru reported the following kmemleak issue: unreferenced object 0x606fd7c44ac8 (size 32): backtrace (crc 0): pcpu_alloc_noprof+0x730/0xeb0 bpf_map_alloc_percpu+0x69/0xc0 prealloc_init+0x9d/0x1b0 htab_map_alloc+0x363/0x510 map_create+0x215/0x3a0 __sys_bpf+0x16b/0x3e0 __x64_sys_bpf+0x18/0x20 do_syscall_64+0x7b/0x150 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Further investigation shows the reason is due to not 8-byte aligned store of percpu pointer in htab_elem_set_ptr(): *(void __percpu **)(l->key + key_size) = pptr; Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size is 4, that means pptr is stored in a location which is 4 byte aligned but not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based on 8 byte stride, so it won't detect above pptr, hence reporting the memory leak. In htab_map_alloc(), we already have htab->elem_size = sizeof(struct htab_elem) + round_up(htab->map.key_size, 8); if (percpu) htab->elem_size += sizeof(void *); else htab->elem_size += round_up(htab->map.value_size, 8); So storing pptr with 8-byte alignment won't cause any problem and can fix kmemleak too. The issue can be reproduced with bpf selftest as well: 1. Enable CONFIG_DEBUG_KMEMLEAK config 2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c. The purpose is to keep map available so kmemleak can be detected. 3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.

Affected

23 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.27-1 (forky)linux 6.12.27-1 (forky)
linuxlinux
linuxlinux>= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 7758e308aeda1038aba1944f7302d34161b3effe7758e308aeda1038aba1944f7302d34161b3effe
linuxlinux>= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 1f1c29aa1934177349c17e3c32e68ec38a7a56df1f1c29aa1934177349c17e3c32e68ec38a7a56df
linuxlinux>= 824bd0ce6c7c43a9e1e210abf124958e54d88342 < 11ba7ce076e5903e7bdc1fd1498979c331b3c28611ba7ce076e5903e7bdc1fd1498979c331b3c286
linuxlinux_kernel< 6.12.266.12.26
linuxlinux_kernel>= 0 < 6.12.27-16.12.27-1
linuxlinux_kernel>= 0 < 6.12.27-16.12.27-1
linuxlinux_kernel>= 0 < 6.14.0-22.226.14.0-22.22
linuxlinux_kernel>= 6.13 < 6.14.56.14.5
msrcazl3_kernel_6.6.104.2-4_on_azure_linux_3.0
msrcazl3_kernel_6.6.112.1-2_on_azure_linux_3.0
msrcazl3_kernel_6.6.117.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-3_on_azure_linux_3.0
msrcazl3_kernel_6.6.121.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.126.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.130.1-3_on_azure_linux_3.0
msrcazl3_kernel_6.6.96.2-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.96.2-2_on_azure_linux_3.0
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_msrc7.0HIGH
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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