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Linux KernelOperating system · Linux

CVE-2024-40942

MEDIUM · 5.5 CVSS v3.1 Published 2024-07-12
Fix available
A fix is available. Upgrade to 4.19.317 / 5.4.279 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: mesh: Fix leak of mesh_preq_queue objects The hwmp code use objects of type mesh_preq_queue, added to a list in ieee80211_if_mesh, to keep track of mpath we need to resolve. If the mpath gets deleted, ex mesh interface is removed, the entries in that list will never get cleaned. Fix this by flushing all corresponding items of the preq_queue in mesh_path_flush_pending(). This should take care of KASAN reports like this: unreferenced object 0xffff00000668d800 (size 128): comm "kworker/u8:4", pid 67, jiffies 4295419552 (age 1836.444s) hex dump (first 32 bytes): 00 1f 05 09 00 00 ff ff 00 d5 68 06 00 00 ff ff ..........h..... 8e 97 ea eb 3e b8 01 00 00 00 00 00 00 00 00 00 ....>........... backtrace: [<000000007302a0b6>] __kmem_cache_alloc_node+0x1e0/0x35c [<00000000049bd418>] kmalloc_trace+0x34/0x80 [<0000000000d792bb>] mesh_queue_preq+0x44/0x2a8 [<00000000c99c3696>] mesh_nexthop_resolve+0x198/0x19c [<00000000926bf598>] ieee80211_xmit+0x1d0/0x1f4 [<00000000fc8c2284>] __ieee80211_subif_start_xmit+0x30c/0x764 [<000000005926ee38>] ieee80211_subif_start_xmit+0x9c/0x7a4 [<000000004c86e916>] dev_hard_start_xmit+0x174/0x440 [<0000000023495647>] __dev_queue_xmit+0xe24/0x111c [<00000000cfe9ca78>] batadv_send_skb_packet+0x180/0x1e4 [<000000007bacc5d5>] batadv_v_elp_periodic_work+0x2f4/0x508 [<00000000adc3cd94>] process_one_work+0x4b8/0xa1c [<00000000b36425d1>] worker_thread+0x9c/0x634 [<0000000005852dd5>] kthread+0x1bc/0x1c4 [<000000005fccd770>] ret_from_fork+0x10/0x20 unreferenced object 0xffff000009051f00 (size 128): comm "kworker/u8:4", pid 67, jiffies 4295419553 (age 1836.440s) hex dump (first 32 bytes): 90 d6 92 0d 00 00 ff ff 00 d8 68 06 00 00 ff ff ..........h..... 36 27 92 e4 02 e0 01 00 00 58 79 06 00 00 ff ff 6'.......Xy..... backtrace: [<000000007302a0b6>] __kmem_cache_alloc_node+0x1e0/0x35c [<00000000049bd418>] kmalloc_trace+0x34/0x80 [<0000000000d792bb>] mesh_queue_preq+0x44/0x2a8 [<00000000c99c3696>] mesh_nexthop_resolve+0x198/0x19c [<00000000926bf598>] ieee80211_xmit+0x1d0/0x1f4 [<00000000fc8c2284>] __ieee80211_subif_start_xmit+0x30c/0x764 [<000000005926ee38>] ieee80211_subif_start_xmit+0x9c/0x7a4 [<000000004c86e916>] dev_hard_start_xmit+0x174/0x440 [<0000000023495647>] __dev_queue_xmit+0xe24/0x111c [<00000000cfe9ca78>] batadv_send_skb_packet+0x180/0x1e4 [<000000007bacc5d5>] batadv_v_elp_periodic_work+0x2f4/0x508 [<00000000adc3cd94>] process_one_work+0x4b8/0xa1c [<00000000b36425d1>] worker_thread+0x9c/0x634 [<0000000005852dd5>] kthread+0x1bc/0x1c4 [<000000005fccd770>] ret_from_fork+0x10/0x20

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-401

Allocated memory is never released on some path, so a long-running service or a repeatedly triggered request steadily consumes memory until performance degrades or the process crashes. Attackers exploit it by simply driving the leaking path. Remediation is pairing every allocation with a release and using ownership patterns or tooling to catch what leaks.

General guidance for the memory leak class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.26, < 4.19.317>= 4.20, < 5.4.279>= 5.5, < 5.10.221>= 5.11, < 5.15.162>= 5.16, < 6.1.95>= 6.2, < 6.6.35>= 6.7, < 6.9.6= 6.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.19.317 / 5.4.279 / 5.10.221 or later
Fixed in 4.19.3175.4.2795.10.221
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 4.19.317+, 5.4.279+, 5.10.221+, or 5.15.162+ (depending on your branch)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine the appropriate upgrade path based on your current kernel branch
  3. Upgrade to a kernel version >= 4.19.317 (if using 4.19.x), >= 5.4.279 (if using 5.4.x), >= 5.10.221 (if using 5.10.x), or >= 5.15.162 (if using 5.15.x)
  4. For Debian/Ubuntu: `apt-get update && apt-get dist-upgrade` followed by system reboot
  5. For RHEL/CentOS: `yum update kernel` followed by system reboot
  6. For other distributions, use the distribution's standard kernel upgrade procedure
  7. Reboot the system to load the patched kernel
  8. Verify the fix is applied by checking the kernel version matches a fixed release
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with custom kernel modules or older software; ensure backups and test in non-production environments first

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-40942 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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