high CVSS 8.4

CVE-2023-52629·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: sh: push-switch: Reorder cleanup operations to avoid use-after-free bug The original code puts flush_work() before timer_shutdown_sync() in switch_drv_remove(). Although we use flush_work() to stop the worker, it could be rescheduled in switch_timer(). As a result, a use-after-free bug can occur. The details are shown below: (cpu 0) | (cpu 1) switch_drv_remove() | flush_work() | ... | switch_timer // timer | schedule_work(&psw->work) timer_shutdown_sync() | ... | switch_work_handler // worker kfree(psw) // free | | psw->state = 0 // use This patch puts timer_shutdown_sync() before flush_work() to mitigate the bugs. As a result, the worker and timer will be stopped safely before the deallocate operations.

Severity: high
Software: Kernel
Fixed in: 6.5.4
Published: 2024-03-29

Affected versions

From: 2.6.20

Until: 6.5.4

Fixed in: 6.5.4

How to fix this CVE

Update your Linux kernel to version 6.5.4 or later to resolve a use-after-free vulnerability in the push-switch driver that could lead to memory corruption. This patch reorders cleanup operations to ensure timers are properly shut down before worker threads are allowed to access freed memory. Systems running kernel versions 2.6.20 through 6.5.3 should prioritize this update.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Check your current kernel version: uname -r
Verify if the affected push-switch driver is loaded: lsmod | grep -i 'push\|switch'
Compare your kernel version against the vulnerability range (2.6.20-6.5.3): if your version falls in this range and you see the driver loaded, your system is vulnerable
After patching, confirm the new kernel is running: uname -r should show 6.5.4 or later, then reboot if needed and verify again

FAQ

What is CVE-2023-52629?

CVE-2023-52629 is a use-after-free vulnerability in the Linux kernel's push-switch driver where a timer can reschedule worker threads after they have been flushed but before the timer itself is shut down, allowing workers to access memory that has already been freed.

Is CVE-2023-52629 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog and no public exploits are available. However, the high CVSS score of 8.4 indicates significant risk if exploited locally.

What versions of Kernel are affected by CVE-2023-52629?

The vulnerability affects Linux kernel versions from 2.6.20 through 6.5.3. Version 6.5.4 and later contain the fix.

How do I check if my server is vulnerable to CVE-2023-52629?

Run 'uname -r' to check your kernel version; if it is between 2.6.20 and 6.5.3, your system is vulnerable. Additionally, run 'lsmod | grep -i push' to confirm if the affected push-switch driver is loaded on your system.

Does Defensia detect CVE-2023-52629?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2023-52629 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2024-42256CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: cifs: Fix server re-repick on subrequest retry When a subrequest is marked for needing retry, netfs will call cifs_prepare_write() which will make cifs repick the server for the op before renegotiating credits; it then calls cifs_issue_write() which invokes smb2_async_writev() - which re-repicks the server. If a different server is then selected, this causes the increment of server->in_flight to happen against one record and the decrement to happen against another, leading to misaccounting. Fix this by just removing the repick code in smb2_async_writev(). As this is only called from netfslib-driven code, cifs_prepare_write() should always have been called first, and so server should never be NULL and the preparatory step is repeated in the event that we do a retry. The problem manifests as a warning looking something like: WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Which may be triggered by a number of different xfstests running against an Azure server in multichannel mode. generic/249 seems the most repeatable, but generic/215, generic/249 and generic/308 may also show it.

CVE-2024-38541CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: of: module: add buffer overflow check in of_modalias() In of_modalias(), if the buffer happens to be too small even for the 1st snprintf() call, the len parameter will become negative and str parameter (if not NULL initially) will point beyond the buffer's end. Add the buffer overflow check after the 1st snprintf() call and fix such check after the strlen() call (accounting for the terminating NUL char).

CVE-2021-47548CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port() The if statement: if (port >= DSAF_GE_NUM) return; limits the value of port less than DSAF_GE_NUM (i.e., 8). However, if the value of port is 6 or 7, an array overflow could occur: port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off; because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6). To fix this possible array overflow, we first check port and if it is greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

CVE-2024-38612CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.

CVE-2022-48716CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: wcd938x: fix incorrect used of portid Mixer controls have the channel id in mixer->reg, which is not same as port id. port id should be derived from chan_info array. So fix this. Without this, its possible that we could corrupt struct wcd938x_sdw_priv by accessing port_map array out of range with channel id instead of port id.

References

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