Linux Kernel up to 5.18.2 list_for_each_entry denial of service

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 5.18.2. Affected by this issue is the function list_for_each_entry. Performing a manipulation results in denial of service. This vulnerability is cataloged as CVE-2022-49393. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.18.2. It has been classified as critical. This affects the function list_for_each_entry. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl This is another instance of incorrect use of list iterator and checking it for NULL. The list iterator value 'map' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty (in this case, the check 'if (!map) {' will always be false and never exit as expected). To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'map' as a dedicated pointer to point to the found element. Without this patch, Kernel crashes with below trace: Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000ffff7fb03750 ... Call trace: fastrpc_map_create+0x70/0x290 [fastrpc] fastrpc_req_mem_map+0xf0/0x2dc [fastrpc] fastrpc_device_ioctl+0x138/0xc60 [fastrpc] __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xd4/0xfc do_el0_svc+0x28/0x90 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xa4/0x130 el0t_64_sync+0x18c/0x190 Code: 14000016 f94000a5 eb05029f 54000260 (b94018a6) ---[ end trace 0000000000000000 ]---

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2022-49393 since 02/26/2025. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.18.3 eliminates this vulnerability. Applying the patch 2d12905aad462383f4e7a5fdb024d2b7ae2d10cf/c5c07c5958cf0c9af6e76813e6de15d42ee49822 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-2107). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• Dell Secure Connect Gateway
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.18.0
• 5.18.1
• 5.18.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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