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Linux KernelOperating system · Linux

CVE-2025-21714

HIGH · 7.8 CVSS v3.1 Published 2025-02-27
Fix available
A fix is available. Upgrade to 6.12.13 / 6.13.2 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: RDMA/mlx5: Fix implicit ODP use after free Prevent double queueing of implicit ODP mr destroy work by using __xa_cmpxchg() to make sure this is the only time we are destroying this specific mr. Without this change, we could try to invalidate this mr twice, which in turn could result in queuing a MR work destroy twice, and eventually the second work could execute after the MR was freed due to the first work, causing a user after free and trace below. refcount_t: underflow; use-after-free. WARNING: CPU: 2 PID: 12178 at lib/refcount.c:28 refcount_warn_saturate+0x12b/0x130 Modules linked in: bonding ib_ipoib vfio_pci ip_gre geneve nf_tables ip6_gre gre ip6_tunnel tunnel6 ipip tunnel4 ib_umad rdma_ucm mlx5_vfio_pci vfio_pci_core vfio_iommu_type1 mlx5_ib vfio ib_uverbs mlx5_core iptable_raw openvswitch nsh rpcrdma ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm ib_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay zram zsmalloc fuse [last unloaded: ib_uverbs] CPU: 2 PID: 12178 Comm: kworker/u20:5 Not tainted 6.5.0-rc1_net_next_mlx5_58c644e #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: events_unbound free_implicit_child_mr_work [mlx5_ib] RIP: 0010:refcount_warn_saturate+0x12b/0x130 Code: 48 c7 c7 38 95 2a 82 c6 05 bc c6 fe 00 01 e8 0c 66 aa ff 0f 0b 5b c3 48 c7 c7 e0 94 2a 82 c6 05 a7 c6 fe 00 01 e8 f5 65 aa ff <0f> 0b 5b c3 90 8b 07 3d 00 00 00 c0 74 12 83 f8 01 74 13 8d 50 ff RSP: 0018:ffff8881008e3e40 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000027 RDX: ffff88852c91b5c8 RSI: 0000000000000001 RDI: ffff88852c91b5c0 RBP: ffff8881dacd4e00 R08: 00000000ffffffff R09: 0000000000000019 R10: 000000000000072e R11: 0000000063666572 R12: ffff88812bfd9e00 R13: ffff8881c792d200 R14: ffff88810011c005 R15: ffff8881002099c0 FS: 0000000000000000(0000) GS:ffff88852c900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5694b5e000 CR3: 00000001153f6003 CR4: 0000000000370ea0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? refcount_warn_saturate+0x12b/0x130 free_implicit_child_mr_work+0x180/0x1b0 [mlx5_ib] process_one_work+0x1cc/0x3c0 worker_thread+0x218/0x3c0 kthread+0xc6/0xf0 ret_from_fork+0x1f/0x30 </TASK>

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:>= 5.5, < 6.12.13>= 6.13, < 6.13.2

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 6.12.13 / 6.13.2 or later
Fixed in 6.12.136.13.2
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 6.12.13+ or 6.13.2+

  1. Check current kernel version with 'uname -r' to confirm affected version
  2. Upgrade to Linux Kernel 6.12.13 or later (if using 6.12.x branch)
  3. Alternatively, upgrade to Linux Kernel 6.13.2 or later (if using 6.13.x branch)
  4. Use distribution-specific package manager (e.g., apt-get, yum, dnf) or build from source
  5. Reboot the system to load the new kernel
  6. Verify the fix by checking kernel version and monitoring for the specific error trace
Caveat Kernel upgrades may require rebuild of third-party kernel modules; ensure driver compatibility with the new kernel version

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 $3,200. 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-2025-21714 in production — separate from our analysis above.

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What this is

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