VulnerabilityPublished 12 Jul 2024Updated 30 Oct 2026

CVE-2024-40998: Linux kernel · ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 15:33 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Apply the official Linux kernel patch that ensures the sysfs interface msg_ratelimit_interval_ms is registered only after the ratelimit_state lock is fully initialized. Until patched, avoid using affected kernel versions in environments where ext4 mounts are critical, or apply backported fixes from trusted sources.

Description

CVE-2024-40998 is a vulnerability in the Linux kernel's ext4 filesystem code where an uninitialized lock (ratelimit_state->lock) can be accessed during the __ext4_fill_super() function execution. This occurs because the sysfs interface for msg_ratelimit_interval_ms is registered before the lock is initialized, allowing concurrent modification of the interval to a non-zero value and subsequent access to the uninitialized lock. This can lead to kernel warnings and potential instability.

Impact

Accessing an uninitialized lock can cause kernel warnings, lockdep errors, and stack traces, potentially leading to kernel instability or crashes during filesystem mount operations. While no direct exploit or code execution is reported, the issue affects kernel reliability and correctness in ext4 filesystem handling.

Summary

The vulnerability in the Linux kernel ext4 module involves accessing an uninitialized ratelimit_state->lock in the __ext4_fill_super() function. The issue arises because the sysfs interface msg_ratelimit_interval_ms is registered before the raw_spin_lock_init(&rs->lock) call, allowing other processes to set rs->interval to a non-zero value while rs->lock remains uninitialized. When ext4_msg is called, it triggers ___ratelimit which attempts to acquire the uninitialized lock, causing kernel lockdep warnings and stack dumps. The fix involves registering the sysfs interface only after all initializations, including rs->lock, are complete.

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What to do

Description

AI analysisMachine-generated, updated 30 Oct 2026, 15:33 UTC

Technical details

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