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Linux KernelOperating system · Linux

CVE-2024-42271

HIGH · 7.8 CVSS v3.1 Published 2024-08-17
Fix available
A fix is available. Upgrade to 4.19.320 / 5.4.282 or later.
See remediation →
80/100
Remediation priority · High
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: net/iucv: fix use after free in iucv_sock_close() iucv_sever_path() is called from process context and from bh context. iucv->path is used as indicator whether somebody else is taking care of severing the path (or it is already removed / never existed). This needs to be done with atomic compare and swap, otherwise there is a small window where iucv_sock_close() will try to work with a path that has already been severed and freed by iucv_callback_connrej() called by iucv_tasklet_fn(). Example: [452744.123844] Call Trace: [452744.123845] ([<0000001e87f03880>] 0x1e87f03880) [452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138 [452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8 [452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48 [452744.124820] [<00000000d5421642>] __fput+0xba/0x268 [452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0 [452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90 [452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8 [452744.125319] Last Breaking-Event-Address: [452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138 [452744.125324] [452744.125325] Kernel panic - not syncing: Fatal exception in interrupt Note that bh_lock_sock() is not serializing the tasklet context against process context, because the check for sock_owned_by_user() and corresponding handling is missing. Ideas for a future clean-up patch: A) Correct usage of bh_lock_sock() in tasklet context, as described in Re-enqueue, if needed. This may require adding return values to the tasklet functions and thus changes to all users of iucv. B) Change iucv tasklet into worker and use only lock_sock() in af_iucv.

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-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free 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:>= 3.4, < 4.19.320>= 4.20, < 5.4.282>= 5.5, < 5.10.224>= 5.11, < 5.15.165>= 5.16, < 6.1.104>= 6.2, < 6.6.45>= 6.7, < 6.10.4= 6.11

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 4.19.320 / 5.4.282 / 5.10.224 or later
Fixed in 4.19.3205.4.2825.10.224
Vendor patch git.kernel.org →
Recommended fix High confidence

Kernel 4.19.320+ / 5.4.282+ / 5.10.224+ / 5.15.165+ or latest stable 6.x release

  1. 1. Identify the current running kernel version using 'uname -r' or 'cat /proc/version'
  2. 2. Determine which version range your current kernel falls into from the affected versions: >= 3.4, < 4.19.320; >= 4.20, < 5.4.282; >= 5.5, < 5.10.224; >= 5.11, < 5.15.165
  3. 3. For kernels in the 4.19.x series, upgrade to kernel version 4.19.320 or later
  4. 4. For kernels in the 5.4.x series, upgrade to kernel version 5.4.282 or later
  5. 5. For kernels in the 5.10.x series, upgrade to kernel version 5.10.224 or later
  6. 6. For kernels in the 5.15.x series, upgrade to kernel version 5.15.165 or later
  7. 7. Alternatively, upgrade to the latest stable kernel (6.x series) which contains the fix
  8. 8. Reboot the system to apply the new kernel
Caveat Standard kernel upgrade considerations apply - ensure compatible drivers and software; some older hardware drivers may not be supported in newer kernels

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

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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-2024-42271 in production — separate from our analysis above.

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