Linux Kernel up to 6.1.41/6.4.6 rcu-tasks pr_info stack-based overflow

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.41/6.4.6. It has been classified as critical. Affected is the function pr_info of the component rcu-tasks. This manipulation causes stack-based overflow. This vulnerability appears as CVE-2023-53558. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.1.41/6.4.6 and classified as critical. Affected by this vulnerability is the function pr_info of the component rcu-tasks. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: rcu-tasks: Avoid pr_info() with spin lock in cblist_init_generic() pr_info() is called with rtp->cbs_gbl_lock spin lock locked. Because pr_info() calls printk() that might sleep, this will result in BUG like below: [ 0.206455] cblist_init_generic: Setting adjustable number of callback queues. [ 0.206463] [ 0.206464] ============================= [ 0.206464] [ BUG: Invalid wait context ] [ 0.206465] 5.19.0-00428-g9de1f9c8ca51 #5 Not tainted [ 0.206466] ----------------------------- [ 0.206466] swapper/0/1 is trying to lock: [ 0.206467] ffffffffa0167a58 (&port_lock_key){....}-{3:3}, at: serial8250_console_write+0x327/0x4a0 [ 0.206473] other info that might help us debug this: [ 0.206473] context-{5:5} [ 0.206474] 3 locks held by swapper/0/1: [ 0.206474] #0: ffffffff9eb597e0 (rcu_tasks.cbs_gbl_lock){....}-{2:2}, at: cblist_init_generic.constprop.0+0x14/0x1f0 [ 0.206478] #1: ffffffff9eb579c0 (console_lock){+.+.}-{0:0}, at: _printk+0x63/0x7e [ 0.206482] #2: ffffffff9ea77780 (console_owner){....}-{0:0}, at: console_emit_next_record.constprop.0+0x111/0x330 [ 0.206485] stack backtrace: [ 0.206486] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-00428-g9de1f9c8ca51 #5 [ 0.206488] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014 [ 0.206489] Call Trace: [ 0.206490] <TASK> [ 0.206491] dump_stack_lvl+0x6a/0x9f [ 0.206493] __lock_acquire.cold+0x2d7/0x2fe [ 0.206496] ? stack_trace_save+0x46/0x70 [ 0.206497] lock_acquire+0xd1/0x2f0 [ 0.206499] ? serial8250_console_write+0x327/0x4a0 [ 0.206500] ? __lock_acquire+0x5c7/0x2720 [ 0.206502] _raw_spin_lock_irqsave+0x3d/0x90 [ 0.206504] ? serial8250_console_write+0x327/0x4a0 [ 0.206506] serial8250_console_write+0x327/0x4a0 [ 0.206508] console_emit_next_record.constprop.0+0x180/0x330 [ 0.206511] console_unlock+0xf7/0x1f0 [ 0.206512] vprintk_emit+0xf7/0x330 [ 0.206514] _printk+0x63/0x7e [ 0.206516] cblist_init_generic.constprop.0.cold+0x24/0x32 [ 0.206518] rcu_init_tasks_generic+0x5/0xd9 [ 0.206522] kernel_init_freeable+0x15b/0x2a2 [ 0.206523] ? rest_init+0x160/0x160 [ 0.206526] kernel_init+0x11/0x120 [ 0.206527] ret_from_fork+0x1f/0x30 [ 0.206530] </TASK> [ 0.207018] cblist_init_generic: Setting shift to 1 and lim to 1. This patch moves pr_info() so that it is called without rtp->cbs_gbl_lock locked.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2023-53558 since 10/04/2025. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/02/2026).

Upgrading to version 6.1.42 or 6.4.7 eliminates this vulnerability. Applying the patch 9027d69221ff96e1356f070f7feb2ff989ae7388/ea9b81c7d9104040b46a84d2303045de267f5557/5fc8cbe4cf0fd34ded8045c385790c3bf04f6785 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 databases at EUVD (EUVD-2023-60050) and CERT Bund (WID-SEC-2025-2194). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• NetApp ActiveIQ Unified Manager
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28
• 6.1.29
• 6.1.30
• 6.1.31
• 6.1.32
• 6.1.33
• 6.1.34
• 6.1.35
• 6.1.36
• 6.1.37
• 6.1.38
• 6.1.39
• 6.1.40
• 6.1.41
• 6.4.0
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 6.4.5
• 6.4.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

Threat Intelligenceinfo

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Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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