Linux KernelOperating system · Linux

CVE-2024-56658

HIGH · 7.8 CVSS v3.1 Published 2024-12-27

Fix available

A fix is available. Upgrade to 3.13 / 3.19 or later.

See remediation →

80/100

Remediation priority · High

Zero-click Patch available

Official description

NVD · unedited

In the Linux kernel, the following vulnerability has been resolved: net: defer final 'struct net' free in netns dismantle Ilya reported a slab-use-after-free in dst_destroy [1] Issue is in xfrm6_net_init() and xfrm4_net_init() : They copy xfrm[46]_dst_ops_template into net->xfrm.xfrm[46]_dst_ops. But net structure might be freed before all the dst callbacks are called. So when dst_destroy() calls later : if (dst->ops->destroy) dst->ops->destroy(dst); dst->ops points to the old net->xfrm.xfrm[46]_dst_ops, which has been freed. See a relevant issue fixed in : ac888d58869b ("net: do not delay dst_entries_add() in dst_release()") A fix is to queue the 'struct net' to be freed after one another cleanup_net() round (and existing rcu_barrier()) [1] BUG: KASAN: slab-use-after-free in dst_destroy (net/core/dst.c:112) Read of size 8 at addr ffff8882137ccab0 by task swapper/37/0 Dec 03 05:46:18 kernel: CPU: 37 UID: 0 PID: 0 Comm: swapper/37 Kdump: loaded Not tainted 6.12.0 #67 Hardware name: Red Hat KVM/RHEL, BIOS 1.16.1-1.el9 04/01/2014 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:124) print_address_description.constprop.0 (mm/kasan/report.c:378) ? dst_destroy (net/core/dst.c:112) print_report (mm/kasan/report.c:489) ? dst_destroy (net/core/dst.c:112) ? kasan_addr_to_slab (mm/kasan/common.c:37) kasan_report (mm/kasan/report.c:603) ? dst_destroy (net/core/dst.c:112) ? rcu_do_batch (kernel/rcu/tree.c:2567) dst_destroy (net/core/dst.c:112) rcu_do_batch (kernel/rcu/tree.c:2567) ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491) ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406) rcu_core (kernel/rcu/tree.c:2825) handle_softirqs (kernel/softirq.c:554) __irq_exit_rcu (kernel/softirq.c:589 kernel/softirq.c:428 kernel/softirq.c:637) irq_exit_rcu (kernel/softirq.c:651) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) </IRQ> <TASK> asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:92 arch/x86/kernel/process.c:743) Code: 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 6e ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 0f 00 2d c7 c9 27 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 RSP: 0018:ffff888100d2fe00 EFLAGS: 00000246 RAX: 00000000001870ed RBX: 1ffff110201a5fc2 RCX: ffffffffb61a3e46 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffb3d4d123 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed11c7e1835d R10: ffff888e3f0c1aeb R11: 0000000000000000 R12: 0000000000000000 R13: ffff888100d20000 R14: dffffc0000000000 R15: 0000000000000000 ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:148) ? cpuidle_idle_call (kernel/sched/idle.c:186) default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) cpuidle_idle_call (kernel/sched/idle.c:186) ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) ? lock_release (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5848) ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406) ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) do_idle (kernel/sched/idle.c:326) cpu_startup_entry (kernel/sched/idle.c:423 (discriminator 1)) start_secondary (arch/x86/kernel/smpboot.c:202 arch/x86/kernel/smpboot.c:282) ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:232) ? soft_restart_cpu (arch/x86/kernel/head_64.S:452) common_startup_64 (arch/x86/kernel/head_64.S:414) </TASK> Dec 03 05:46:18 kernel: Allocated by task 12184: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 mm/kasan/common.c:69) __kasan_slab_alloc (mm/kasan/common.c:319 mm/kasan/common.c:345) kmem_cache_alloc_noprof (mm/slub.c:4085 mm/slub.c:4134 mm/slub.c:4141) copy_net_ns (net/core/net_namespace.c:421 net/core/net_namespace.c:480) create_new_namespaces ---truncated---

Technical summary

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

NVD · CPE data

Linux KernelOperating system

Affected:>= 3.12.54, < 3.13>= 3.18.27, < 3.19>= 4.1.17, < 4.2>= 4.3.5, < 6.1.121>= 6.2, < 6.6.67>= 6.7, < 6.12.6= 6.13

CVSS breakdown

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

dbcve · scoped

Upgrade available Upgrade to 3.13 / 3.19 / 4.2 or later

Fixed in 3.133.194.2

Vendor patch git.kernel.org →

Recommended fix High confidence

Linux Kernel >= 6.1.121 (or a distribution-provided patch that includes commit 0f6ede9fbc747e2553612271bce108f7517e7a45)

Identify the currently running kernel version using `uname -r`
Check if your distribution has released a patched kernel package for your version
If no patched package is available, upgrade to a stable kernel version >= 6.1.121 (or >= 6.6.x for newer systems)
Reboot into the updated kernel to apply the fix
Verify the fix is applied by checking the kernel version and confirming the commit is included: `cat /proc/version` or check kernel config for CONFIG_XFRM

Caveat Kernel upgrades may require rebuilding out-of-tree kernel modules; ensure driver compatibility before upgrading

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

Scan for this in your stack

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-56658 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2024-56658?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsUpgrade to 3.13 / 3.19 or later

Severity 7.8 High

Exploit likelihood EPSS, next 30 days 0.2%

Affects: Linux Kernel

Remediation

A high-priority fix

Get a fix

Estimated effortfrom ~18 hrs

ComplexityComplex

Typical engagementfrom $3,200

What a fix involves

We scope it with you and confirm a fixed quote
A specialist builds a reviewed fix
You deploy it to staging first
Optional re-test once it’s live

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2024-56658 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Scan for this in your stack

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

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Remediation

References