critical CVSS 9.8

CVE-2024-36031·Kernel vulnerability

In 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.

Severity
critical
Software
Kernel
Fixed in
6.9.1
Published
2024-05-30

Affected versions

From: 6.9

Until: 6.9.1

Fixed in: 6.9.1

How to fix this CVE

Update your Linux kernel to version 6.9.1 or later to fix the key expiration handling issue that was causing DNS resolution failures. This patch restores proper conditional logic for setting key expiry times, preventing user-space configured expirations from being overwritten to permanent. Kernel updates typically require a system reboot to take effect.

sudo dnf update kernel kernel-devel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Check kernel version: uname -r — verify if it is between 6.9 and 6.9.1 (vulnerable range)
  2. Confirm the kernel-keys subsystem is in use: cat /proc/keys | head -5 — look for key entries to verify key management is active
  3. Monitor DNS resolution failures: grep -i 'dns.*timeout\|dns.*fail' /var/log/syslog or journalctl -u systemd-resolved | grep -i error to detect DNS query failures caused by expired key caching
  4. Verify the patch: cat /boot/config-$(uname -r) | grep CONFIG_KEYS to ensure the fixed kernel version contains key management support, then compare kernel version against 6.9.1+

FAQ

What is CVE-2024-36031?

This vulnerability exists in the Linux kernel's key management subsystem, where key expiration times are unconditionally reset to permanent (TIME64_MAX) during instantiation. This breaks DNS caching mechanisms that rely on time-limited key validity, causing DNS resolution to fail or stall.

Is CVE-2024-36031 being actively exploited?

No, this CVE is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploit code is currently available. However, it causes significant operational impact to DNS services and should be patched promptly.

What versions of Kernel are affected by CVE-2024-36031?

Linux kernel versions 6.9 through 6.9.1 are vulnerable. The fix is included in kernel 6.9.1 and all subsequent releases.

How do I check if my server is vulnerable to CVE-2024-36031?

Run uname -r and check if the output is 6.9 or 6.9.1. If it shows 6.9.0, 6.9, or 6.9.1, your system is vulnerable and requires an immediate kernel update to 6.9.2 or later.

Does Defensia detect CVE-2024-36031?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-36031 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-2022-48716CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: wcd938x: fix incorrect used of portid Mixer controls have the channel id in mixer->reg, which is not same as port id. port id should be derived from chan_info array. So fix this. Without this, its possible that we could corrupt struct wcd938x_sdw_priv by accessing port_map array out of range with channel id instead of port id.
CVE-2024-38541CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: of: module: add buffer overflow check in of_modalias() In of_modalias(), if the buffer happens to be too small even for the 1st snprintf() call, the len parameter will become negative and str parameter (if not NULL initially) will point beyond the buffer's end. Add the buffer overflow check after the 1st snprintf() call and fix such check after the strlen() call (accounting for the terminating NUL char).
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.

References

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