cbcvebase.
CVE-2024-56640
published 2024-12-27

CVE-2024-56640: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix LGR and link use-after-free issue We encountered a LGR/link use-after-free…

PriorityP339high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.23%
13.5th percentile
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix LGR and link use-after-free issue We encountered a LGR/link use-after-free issue, which manifested as the LGR/link refcnt reaching 0 early and entering the clear process, making resource access unsafe. refcount_t: addition on 0; use-after-free. WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140 Workqueue: events smc_lgr_terminate_work [smc] Call trace: refcount_warn_saturate+0x9c/0x140 __smc_lgr_terminate.part.45+0x2a8/0x370 [smc] smc_lgr_terminate_work+0x28/0x30 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118 or refcount_t: underflow; use-after-free. WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140 Workqueue: smc_hs_wq smc_listen_work [smc] Call trace: refcount_warn_saturate+0xf0/0x140 smcr_link_put+0x1cc/0x1d8 [smc] smc_conn_free+0x110/0x1b0 [smc] smc_conn_abort+0x50/0x60 [smc] smc_listen_find_device+0x75c/0x790 [smc] smc_listen_work+0x368/0x8a0 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118 It is caused by repeated release of LGR/link refcnt. One suspect is that smc_conn_free() is called repeatedly because some smc_conn_free() from server listening path are not protected by sock lock. e.g. Calls under socklock | smc_listen_work lock_sock(sk) | smc_conn_abort smc_conn_free | \- smc_conn_free \- smcr_link_put | \- smcr_link_put (duplicated) release_sock(sk) So here add sock lock protection in smc_listen_work() path, making it exclusive with other connection operations.

Affected

27 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
debianlinux-6.1< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
linuxlinux
linuxlinux>= 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 < f502a88fdd415647a1f2dc45fac71b9c522a052bf502a88fdd415647a1f2dc45fac71b9c522a052b
linuxlinux>= 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 < 0cf598548a6c36d90681d53c6b77d52363f2f2950cf598548a6c36d90681d53c6b77d52363f2f295
linuxlinux>= 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 < 673d606683ac70bc074ca6676b938bff18635226673d606683ac70bc074ca6676b938bff18635226
linuxlinux>= 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 < 6f0ae06a234a78ae137064f2c89135ac078a00eb6f0ae06a234a78ae137064f2c89135ac078a00eb
linuxlinux>= 3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 < 2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d72c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.1.123-16.1.123-1
linuxlinux_kernel>= 0 < 6.12.5-16.12.5-1
linuxlinux_kernel>= 0 < 6.12.5-16.12.5-1
linuxlinux_kernel>= 0 < 5.15.0-135.1465.15.0-135.146
linuxlinux_kernel>= 0 < 6.8.0-58.606.8.0-58.60
linuxlinux_kernel>= 0 < 5.4.0-227.2475.4.0-227.247
linuxlinux_kernel>= 4.18 < 5.15.1745.15.174
linuxlinux_kernel>= 5.16 < 6.1.1206.1.120
linuxlinux_kernel>= 6.2 < 6.6.666.6.66
linuxlinux_kernel>= 6.7 < 6.12.56.12.5
msrcazl3_kernel_6.6.64.2-9_on_azure_linux_3.0
msrcazl3_kernel_6.6.76.1-1_on_azure_linux_3.0
msrccbl2_kernel_5.15.173.1-2_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.176.3-1_on_cbl_mariner_2.0
ubuntulinux-azure-5.4
ubuntulinux-bluefield

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.