high CVSS 7.8

CVE-2022-48950·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: perf: Fix perf_pending_task() UaF Per syzbot it is possible for perf_pending_task() to run after the event is free()'d. There are two related but distinct cases: - the task_work was already queued before destroying the event; - destroying the event itself queues the task_work. The first cannot be solved using task_work_cancel() since perf_release() itself might be called from a task_work (____fput), which means the current->task_works list is already empty and task_work_cancel() won't be able to find the perf_pending_task() entry. The simplest alternative is extending the perf_event lifetime to cover the task_work. The second is just silly, queueing a task_work while you know the event is going away makes no sense and is easily avoided by re-arranging how the event is marked STATE_DEAD and ensuring it goes through STATE_OFF on the way down.

Severity
high
Software
Kernel
Fixed in
6.0.14
Published
2024-10-21

Affected versions

From: 5.16

Until: 6.0.14

Fixed in: 6.0.14

How to fix this CVE

Update your Linux kernel to version 6.0.14 or later to resolve a use-after-free vulnerability in the perf event handling subsystem. This vulnerability allows a freed perf event to be accessed during asynchronous task work cleanup, potentially leading to kernel crashes or privilege escalation. Systems running kernel versions 5.16 through 6.0.13 should prioritize this patch and reboot after updating.

sudo dnf update kernel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to check your current kernel version and compare against the vulnerable range (5.16.x through 6.0.13)
  2. Verify perf event subsystem is enabled by checking 'cat /boot/config-$(uname -r) | grep CONFIG_PERF_EVENTS' — if it returns 'CONFIG_PERF_EVENTS=y', the subsystem is active
  3. Search kernel logs for perf-related crashes with 'dmesg | grep -i perf' or 'journalctl -xe | grep -i perf' to identify potential exploitation attempts
  4. After patching, confirm the new kernel is running with 'uname -r' and verify it matches 6.0.14 or later

FAQ

What is CVE-2022-48950?

CVE-2022-48950 is a use-after-free vulnerability in the Linux kernel's perf (performance monitoring) event subsystem where asynchronous task work can attempt to access a performance event after it has been freed from memory, resulting in kernel instability or potential privilege escalation.

Is CVE-2022-48950 being actively exploited?

No, there is no public evidence of active exploitation in the wild. This vulnerability was discovered through fuzzing (syzbot) and is not listed on CISA's Known Exploited Vulnerabilities catalog.

What versions of Kernel are affected by CVE-2022-48950?

Linux kernel versions 5.16.0 through 6.0.13 are affected. The vulnerability was fixed in kernel 6.0.14 and later stable releases.

How do I check if my server is vulnerable to CVE-2022-48950?

Run 'uname -r' and compare your kernel version against 5.16.0 to 6.0.13. If your version falls within this range, your system is vulnerable and requires a kernel update.

Does Defensia detect CVE-2022-48950?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2022-48950 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-2024-36031CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: keys: Fix overwrite of key expiration on instantiation The expiry time of a key is unconditionally overwritten during instantiation, defaulting to turn it permanent. This causes a problem for DNS resolution as the expiration set by user-space is overwritten to TIME64_MAX, disabling further DNS updates. Fix this by restoring the condition that key_set_expiry is only called when the pre-parser sets a specific expiry.
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-2024-38623CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Use variable length array instead of fixed size Should fix smatch warning: ntfs_set_label() error: __builtin_memcpy() 'uni->name' too small (20 vs 256)
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.

References

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