high CVSS 7.8

CVE-2023-52926·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: IORING_OP_READ did not correctly consume the provided buffer list when read i/o returned < 0 (except for -EAGAIN and -EIOCBQUEUED return). This can lead to a potential use-after-free when the completion via io_rw_done runs at separate context.

Severity
high
Software
Kernel
Fixed in
6.6.68
Published
2025-02-24

Affected versions

From: 6.2

Until: 6.6.68

Fixed in: 6.6.68

How to fix this CVE

Update your Linux kernel to version 6.6.68 or later to resolve a buffer management issue in the io_uring subsystem. This vulnerability affects kernel versions 6.2 through 6.6.67 and could lead to memory safety issues when asynchronous read operations fail under specific conditions. Apply the kernel update and reboot your system at your earliest convenience.

sudo dnf update kernel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to display the currently running kernel version and compare against 6.6.68
  2. Check if io_uring is enabled in your kernel configuration by running 'grep CONFIG_IO_URING /boot/config-$(uname -r)' — if it returns 'y', the subsystem is active
  3. Search system logs for io_uring-related errors or memory faults: 'sudo journalctl -b | grep -i "io_uring\|use.after.free\|buffer"'
  4. After applying the kernel update, verify the new version with 'uname -r' and confirm it is 6.6.68 or later

FAQ

What is CVE-2023-52926?

CVE-2023-52926 is a buffer lifecycle management flaw in the Linux kernel's io_uring subsystem that occurs when read operations encounter errors. The kernel fails to properly release buffers from the provided buffer list in certain error conditions, potentially leading to use-after-free vulnerabilities when asynchronous I/O completions execute in a different execution context.

Is CVE-2023-52926 being actively exploited?

No, CVE-2023-52926 is not listed on the CISA Known Exploited Vulnerabilities catalog, and no public proof-of-concept exploits have been disclosed. However, as a high-severity memory safety issue, timely patching is still recommended.

What versions of Kernel are affected by CVE-2023-52926?

Linux kernel versions 6.2 through 6.6.67 are affected. The vulnerability was fixed in kernel 6.6.68 and later releases.

How do I check if my server is vulnerable to CVE-2023-52926?

Run 'uname -r' to check your kernel version. If it shows a version between 6.2 and 6.6.67 (inclusive), your system is vulnerable. Additionally, confirm io_uring support with 'grep CONFIG_IO_URING /boot/config-$(uname -r)'.

Does Defensia detect CVE-2023-52926?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel package is installed on a monitored server running version 6.2 through 6.6.67, CVE-2023-52926 will appear in your dashboard with automated 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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