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Linux KernelOperating system · Linux

CVE-2025-21790

MEDIUM · 5.5 CVSS v3.1 Published 2025-02-27
Fix available
A fix is available. Upgrade to 6.1.129 / 6.6.79 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: vxlan: check vxlan_vnigroup_init() return value vxlan_init() must check vxlan_vnigroup_init() success otherwise a crash happens later, spotted by syzbot. Oops: general protection fault, probably for non-canonical address 0xdffffc000000002c: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000160-0x0000000000000167] CPU: 0 UID: 0 PID: 7313 Comm: syz-executor147 Not tainted 6.14.0-rc1-syzkaller-00276-g69b54314c975 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:vxlan_vnigroup_uninit+0x89/0x500 drivers/net/vxlan/vxlan_vnifilter.c:912 Code: 00 48 8b 44 24 08 4c 8b b0 98 41 00 00 49 8d 86 60 01 00 00 48 89 c2 48 89 44 24 10 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 4d 04 00 00 49 8b 86 60 01 00 00 48 ba 00 00 00 RSP: 0018:ffffc9000cc1eea8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff8672effb RDX: 000000000000002c RSI: ffffffff8672ecb9 RDI: ffff8880461b4f18 RBP: ffff8880461b4ef4 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000020000 R13: ffff8880461b0d80 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007fecfa95d6c0(0000) GS:ffff88806a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fecfa95cfb8 CR3: 000000004472c000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> vxlan_uninit+0x1ab/0x200 drivers/net/vxlan/vxlan_core.c:2942 unregister_netdevice_many_notify+0x12d6/0x1f30 net/core/dev.c:11824 unregister_netdevice_many net/core/dev.c:11866 [inline] unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11736 register_netdevice+0x1829/0x1eb0 net/core/dev.c:10901 __vxlan_dev_create+0x7c6/0xa30 drivers/net/vxlan/vxlan_core.c:3981 vxlan_newlink+0xd1/0x130 drivers/net/vxlan/vxlan_core.c:4407 rtnl_newlink_create net/core/rtnetlink.c:3795 [inline] __rtnl_newlink net/core/rtnetlink.c:3906 [inline]

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-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference 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:>= 5.18, < 6.1.129>= 6.2, < 6.6.79>= 6.7, < 6.12.16>= 6.13, < 6.13.4= 6.14

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 6.1.129 / 6.6.79 / 6.12.16 or later
Fixed in 6.1.1296.6.796.12.16
Vendor patch git.kernel.org →
Recommended fix High confidence

6.1.129 or 6.6.79 or 6.12.16 or 6.13.4 (depending on which kernel branch is in use)

  1. 1. Identify the currently running Linux kernel version using `uname -r`
  2. 2. Determine which stable kernel series your distribution supports (e.g., 6.1.x, 6.6.x, 6.7.x, 6.12.x, or 6.13.x)
  3. 3. Upgrade the kernel to a version >= the first fixed release in your series: for 6.1.x upgrade to 6.1.129+, for 6.2-6.6.x upgrade to 6.6.79+, for 6.7-6.12.x upgrade to 6.12.16+, for 6.13.x upgrade to 6.13.4+
  4. 4. On Debian/Ubuntu: run `apt-get update && apt-get dist-upgrade` or install the specific linux-image package from security updates
  5. 5. On RHEL/CentOS: run `yum update kernel` or `dnf update kernel`
  6. 6. On other distributions: obtain the updated kernel from your vendor's security advisory for this CVE
  7. 7. Reboot the system into the new kernel
  8. 8. Verify the fix is applied by checking the kernel version with `uname -r` and confirming it meets the minimum fixed version requirement
Caveat Kernel upgrades may require system downtime and could potentially introduce incompatibilities with custom modules; ensure backups and test in staging if possible

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 $2,850. 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-2025-21790 in production — separate from our analysis above.

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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
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