high CVSS 7.8

CVE-2024-57917·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: topology: Keep the cpumask unchanged when printing cpumap During fuzz testing, the following warning was discovered: different return values (15 and 11) from vsnprintf("%*pbl ", ...) test:keyward is WARNING in kvasprintf WARNING: CPU: 55 PID: 1168477 at lib/kasprintf.c:30 kvasprintf+0x121/0x130 Call Trace: kvasprintf+0x121/0x130 kasprintf+0xa6/0xe0 bitmap_print_to_buf+0x89/0x100 core_siblings_list_read+0x7e/0xb0 kernfs_file_read_iter+0x15b/0x270 new_sync_read+0x153/0x260 vfs_read+0x215/0x290 ksys_read+0xb9/0x160 do_syscall_64+0x56/0x100 entry_SYSCALL_64_after_hwframe+0x78/0xe2 The call trace shows that kvasprintf() reported this warning during the printing of core_siblings_list. kvasprintf() has several steps: (1) First, calculate the length of the resulting formatted string. (2) Allocate a buffer based on the returned length. (3) Then, perform the actual string formatting. (4) Check whether the lengths of the formatted strings returned in steps (1) and (2) are consistent. If the core_cpumask is modified between steps (1) and (3), the lengths obtained in these two steps may not match. Indeed our test includes cpu hotplugging, which should modify core_cpumask while printing. To fix this issue, cache the cpumask into a temporary variable before calling cpumap_print_{list, cpumask}_to_buf(), to keep it unchanged during the printing process.

Severity: high
Software: Kernel
Fixed in: 6.12.10
Published: 2025-01-19

Affected versions

From: 6.7

Until: 6.12.10

Fixed in: 6.12.10

How to fix this CVE

Update your Linux kernel to version 6.12.10 or later to resolve a race condition in CPU topology mask printing that can cause kernel warnings and system instability during CPU hotplug events. Systems running kernel versions 6.7 through 6.12.9 should prioritize this patch to prevent unpredictable behavior when CPUs are dynamically added or removed.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Step 1: Check your current kernel version by running `uname -r` and compare against 6.12.10
Step 2: Verify CPU topology files exist at `/sys/devices/system/cpu/cpu*/topology/` which are affected by this vulnerability
Step 3: Search kernel logs for warnings with `grep -i 'kvasprintf\|core_siblings_list' /var/log/kern.log /var/log/messages` to identify if the race condition has been triggered
Step 4: After patching, reboot with `sudo reboot` and confirm new kernel version with `uname -r`, then perform CPU hotplug tests to verify stable topology reporting

FAQ

What is CVE-2024-57917?

CVE-2024-57917 is a race condition in the Linux kernel's CPU topology mask printing functionality where the cpumask can change between length calculation and actual formatting, causing kvasprintf() to report length mismatches and kernel warnings during CPU hotplug operations.

Is CVE-2024-57917 being actively exploited?

No, CVE-2024-57917 is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available. However, it can cause denial of service through kernel warnings during routine CPU hotplugging.

What versions of Kernel are affected by CVE-2024-57917?

Linux kernel versions 6.7 through 6.12.9 are vulnerable. The fix is included in kernel 6.12.10 and later.

How do I check if my server is vulnerable to CVE-2024-57917?

Run `uname -r` to check your kernel version. If it outputs a version between 6.7 and 6.12.9, your system is vulnerable. Additionally, check logs with `grep 'kvasprintf' /var/log/kern.log` for signs of the race condition being triggered.

Does Defensia detect CVE-2024-57917?

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-2024-57917 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-2024-36031CVSS 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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