dbcve.org
Linux KernelOperating system · Linux

CVE-2023-52851

HIGH · 7.8 CVSS v3.1 Published 2024-05-21
Fix available
A fix is available. Upgrade to 6.1.63 / 6.5.12 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: IB/mlx5: Fix init stage error handling to avoid double free of same QP and UAF In the unlikely event that workqueue allocation fails and returns NULL in mlx5_mkey_cache_init(), delete the call to mlx5r_umr_resource_cleanup() (which frees the QP) in mlx5_ib_stage_post_ib_reg_umr_init(). This will avoid attempted double free of the same QP when __mlx5_ib_add() does its cleanup. Resolves a splat: Syzkaller reported a UAF in ib_destroy_qp_user workqueue: Failed to create a rescuer kthread for wq "mkey_cache": -EINTR infiniband mlx5_0: mlx5_mkey_cache_init:981:(pid 1642): failed to create work queue infiniband mlx5_0: mlx5_ib_stage_post_ib_reg_umr_init:4075:(pid 1642): mr cache init failed -12 ================================================================== BUG: KASAN: slab-use-after-free in ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) Read of size 8 at addr ffff88810da310a8 by task repro_upstream/1642 Call Trace: <TASK> kasan_report (mm/kasan/report.c:590) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2073) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4178) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... </TASK> Allocated by task 1642: __kmalloc (./include/linux/kasan.h:198 mm/slab_common.c:1026 mm/slab_common.c:1039) create_qp (./include/linux/slab.h:603 ./include/linux/slab.h:720 ./include/rdma/ib_verbs.h:2795 drivers/infiniband/core/verbs.c:1209) ib_create_qp_kernel (drivers/infiniband/core/verbs.c:1347) mlx5r_umr_resource_init (drivers/infiniband/hw/mlx5/umr.c:164) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4070) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ... Freed by task 1642: __kmem_cache_free (mm/slub.c:1826 mm/slub.c:3809 mm/slub.c:3822) ib_destroy_qp_user (drivers/infiniband/core/verbs.c:2112) mlx5r_umr_resource_cleanup (drivers/infiniband/hw/mlx5/umr.c:198) mlx5_ib_stage_post_ib_reg_umr_init (drivers/infiniband/hw/mlx5/main.c:4076 drivers/infiniband/hw/mlx5/main.c:4065) __mlx5_ib_add (drivers/infiniband/hw/mlx5/main.c:4168) mlx5r_probe (drivers/infiniband/hw/mlx5/main.c:4402) ...

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-415

The same block of memory is freed twice, corrupting the allocator's bookkeeping in ways an attacker can shape toward code execution. It usually stems from tangled ownership of a pointer. The fix is clear, single ownership of each allocation and clearing pointers once they are freed.

General guidance for the double 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:>= 5.19, < 6.1.63>= 6.2, < 6.5.12>= 6.6, < 6.6.2

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 6.1.63 / 6.5.12 / 6.6.2 or later
Fixed in 6.1.636.5.126.6.2
Vendor patch git.kernel.org →
Recommended fix High confidence

6.1.63 (or 6.5.12 or 6.6.2 depending on branch)

  1. Identify the current running kernel version using `uname -r`
  2. Verify the exact kernel version is within the affected range: >= 5.19 and < 6.1.63, OR >= 6.2 and < 6.5.12, OR >= 6.6 and < 6.6.2
  3. Plan maintenance window for kernel upgrade (requires system reboot)
  4. Upgrade the Linux kernel to version 6.1.63 or later (recommended for LTS branches), OR 6.5.12 or later, OR 6.6.2 or later
  5. Reboot the system to load the fixed kernel
  6. Verify the fix is applied by checking kernel version with `uname -r`
  7. Confirm the mlx5 driver loads without errors: `dmesg | grep -i mlx5`
Caveat Kernel upgrade carries standard reboot requirement and potential driver compatibility risk; verify mlx5 driver version matches hardware

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 $1,950. 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-2023-52851 in production — separate from our analysis above.

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