critical CVSS 9.1

CVE-2023-52832·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: don't return unset power in ieee80211_get_tx_power() We can get a UBSAN warning if ieee80211_get_tx_power() returns the INT_MIN value mac80211 internally uses for "unset power level". UBSAN: signed-integer-overflow in net/wireless/nl80211.c:3816:5 -2147483648 * 100 cannot be represented in type 'int' CPU: 0 PID: 20433 Comm: insmod Tainted: G WC OE Call Trace: dump_stack+0x74/0x92 ubsan_epilogue+0x9/0x50 handle_overflow+0x8d/0xd0 __ubsan_handle_mul_overflow+0xe/0x10 nl80211_send_iface+0x688/0x6b0 [cfg80211] [...] cfg80211_register_wdev+0x78/0xb0 [cfg80211] cfg80211_netdev_notifier_call+0x200/0x620 [cfg80211] [...] ieee80211_if_add+0x60e/0x8f0 [mac80211] ieee80211_register_hw+0xda5/0x1170 [mac80211] In this case, simply return an error instead, to indicate that no data is available.

Severity: critical
Software: Kernel
Fixed in: 6.6.3
Published: 2024-05-21

Affected versions

From: 6.6

Until: 6.6.3

Fixed in: 6.6.3

How to fix this CVE

Update your Linux kernel to version 6.6.3 or later to resolve this integer overflow vulnerability in the mac80211 wireless subsystem. The vulnerability occurs when the power management function attempts to return an uninitialized internal value, triggering undefined behavior during integer multiplication. Kernel updates should be applied promptly and systems should be rebooted to activate the patched kernel.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Run 'uname -r' to check the currently running kernel version and compare against 6.6.3
Execute 'cat /proc/cmdline' to verify which kernel was booted at system startup
Check 'dmesg | grep -i ubsan' to look for any UBSAN warnings related to signed integer overflow in nl80211
After patching, reboot the system with 'sudo reboot' and confirm the new kernel version with 'uname -r' to ensure the fix is active

FAQ

What is CVE-2023-52832?

CVE-2023-52832 is an integer overflow vulnerability in the Linux kernel's mac80211 wireless driver where the ieee80211_get_tx_power() function returns an uninitialized sentinel value that causes signed integer overflow when multiplied during netlink communication, triggering undefined behavior.

Is CVE-2023-52832 being actively exploited?

No, CVE-2023-52832 is not currently listed as actively exploited by CISA, and no public exploits are available. However, the critical CVSS score of 9.1 indicates significant impact potential.

What versions of Kernel are affected by CVE-2023-52832?

Linux kernel versions 6.6 through 6.6.2 are affected. Kernel 6.6.3 and later versions contain the patch that properly handles unset power level values.

How do I check if my server is vulnerable to CVE-2023-52832?

Run 'uname -r' and check if the output shows a version number starting with 6.6 but less than 6.6.3 (e.g., 6.6.0, 6.6.1, 6.6.2). If so, your system is vulnerable.

Does Defensia detect CVE-2023-52832?

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-2023-52832 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-2024-39462CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: clk: bcm: dvp: Assign ->num before accessing ->hws Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer about the number of elements in hws, so that it can warn when hws is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in clk_dvp_probe() due to ->num being assigned after ->hws has been accessed: UBSAN: array-index-out-of-bounds in drivers/clk/bcm/clk-bcm2711-dvp.c:59:2 index 0 is out of range for type 'struct clk_hw *[] __counted_by(num)' (aka 'struct clk_hw *[]') Move the ->num initialization to before the first access of ->hws, which clears up the warning.

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-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-2024-36031CVSS 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.

References

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