high CVSS 7.8

CVE-2023-52483·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: mctp: perform route lookups under a RCU read-side lock Our current route lookups (mctp_route_lookup and mctp_route_lookup_null) traverse the net's route list without the RCU read lock held. This means the route lookup is subject to preemption, resulting in an potential grace period expiry, and so an eventual kfree() while we still have the route pointer. Add the proper read-side critical section locks around the route lookups, preventing premption and a possible parallel kfree. The remaining net->mctp.routes accesses are already under a rcu_read_lock, or protected by the RTNL for updates. Based on an analysis from Sili Luo <rootlab@huawei.com>, where introducing a delay in the route lookup could cause a UAF on simultaneous sendmsg() and route deletion.

Severity
high
Software
Kernel
Fixed in
6.5.8
Published
2024-02-29

Affected versions

From: 6.2

Until: 6.5.8

Fixed in: 6.5.8

How to fix this CVE

Update your Linux kernel to version 6.5.8 or later to resolve a use-after-free vulnerability in MCTP route lookups. This vulnerability occurs when RCU read-side locks are missing during route traversal, allowing concurrent route deletion to cause memory corruption. Apply the kernel security patch immediately on systems running kernel versions 6.2 through 6.5.7.

sudo dnf update kernel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your current kernel version with `uname -r` and verify if it falls within 6.2.x to 6.5.7 range
  2. Step 2: Verify MCTP support is enabled by checking if `/proc/net/mctp` exists or checking kernel config with `grep CONFIG_MCTP /boot/config-$(uname -r)`
  3. Step 3: Search system logs for UAF-related crashes using `dmesg | grep -i 'use-after-free\|uaf\|kasan'` and `journalctl -xe | grep -i mctp`
  4. Step 4: After patching, confirm the new kernel version with `uname -r` and verify it is 6.5.8 or later, then reboot if necessary

FAQ

What is CVE-2023-52483?

This vulnerability is a use-after-free condition in the Linux kernel's MCTP (Management Component Transport Protocol) subsystem caused by missing RCU read-side critical section locks during route lookups. An attacker with local access can trigger simultaneous sendmsg() calls and route deletions to cause memory corruption and potential privilege escalation.

Is CVE-2023-52483 being actively exploited?

No, this vulnerability is not listed on CISA's Known Exploited Vulnerabilities catalog and no public exploits are available, though the vulnerability requires local access to exploit.

What versions of Kernel are affected by CVE-2023-52483?

Linux kernel versions 6.2.0 through 6.5.7 are affected; kernel 6.5.8 and later contain the fix.

How do I check if my server is vulnerable to CVE-2023-52483?

Run `uname -r` to check your kernel version; if the output shows a version between 6.2 and 6.5.7, and MCTP is enabled (check with `grep CONFIG_MCTP /boot/config-$(uname -r)`), your system is vulnerable.

Does Defensia detect CVE-2023-52483?

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-2023-52483 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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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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