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NVD / CVE Program· CNA Linux

CVE-2025-21716: vxlan: Fix uninit-value in vxlan_vnifilter_dump()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1693d1fade71646a0731b6b213298cb443d186ea, 5066293b9b7046a906eff60e3949a887ae185a43, a84d511165d6ba7f331b90ae6b6ce180ec534daa; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.78.1-3; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.78.1-3.

Low priority for now. Upgrade to Linux Linux 1693d1fade71646a0731b6b213298cb443d186ea, 5066293b9b7046a906eff60e3949a887ae185a43, a84d511165d6ba7f331b90ae6b6ce180ec534daa; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.78.1-3; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.78.1-3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: vxlan: Fix uninit-value in vxlan_vnifilter_dump() KMSAN reported an uninit-value access in vxlan_vnifilter_dump() [1]. If the length of the netlink message payload is less than sizeof(struct tunnel_msg), vxlan_vnifilter_dump() accesses bytes beyond the message. This can lead to uninit-value access. Fix this by returning an error in such situations. [1] BUG: KMSAN: uninit-value in vxlan_vnifilter_dump+0x328/0x920 drivers/net/vxlan/vxlan_vnifilter.c:422 vxlan_vnifilter_dump+0x328/0x920 drivers/net/vxlan/vxlan_vnifilter.c:422 rtnl_dumpit+0xd5/0x2f0 net/core/rtnetlink.c:6786 netlink_dump+0x93e/0x15f0 net/netlink/af_netlink.c:2317 __netlink_dump_start+0x716/0xd60 net/netlink/af_netlink.c:2432 netlink_dump_start include/linux/netlink.h:340 [inline] rtnetlink_dump_start net/core/rtnetlink.c:6815 [inline] rtnetlink_rcv_msg+0x1256/0x14a0 net/core/rtnetlink.c:6882 netlink_rcv_skb+0x467/0x660 net/netlink/af_netlink.c:2542 rtnetlink_rcv+0x35/0x40 net/core/rtnetlink.c:6944 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0xed6/0x1290 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x1092/0x1230 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:726 ____sys_sendmsg+0x7f4/0xb50 net/socket.c:2583 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2637 __sys_sendmsg net/socket.c:2669 [inline] __do_sys_sendmsg net/socket.c:2674 [inline] __se_sys_sendmsg net/socket.c:2672 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2672 x64_sys_call+0x3878/0x3d90 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4110 [inline] slab_alloc_node mm/slub.c:4153 [inline] kmem_cache_alloc_node_noprof+0x800/0xe80 mm/slub.c:4205 kmalloc_reserve+0x13b/0x4b0 net/core/skbuff.c:587 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1323 [inline] netlink_alloc_large_skb+0xa5/0x280 net/netlink/af_netlink.c:1196 netlink_sendmsg+0xac9/0x1230 net/netlink/af_netlink.c:1866 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:726 ____sys_sendmsg+0x7f4/0xb50 net/socket.c:2583 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2637 __sys_sendmsg net/socket.c:2669 [inline] __do_sys_sendmsg net/socket.c:2674 [inline] __se_sys_sendmsg net/socket.c:2672 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2672 x64_sys_call+0x3878/0x3d90 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 30991 Comm: syz.4.10630 Not tainted 6.12.0-10694-gc44daa7e3c73 #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 27, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 10th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
5.5
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-21716

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.18 and later · before 6.1.129
  • linux linux kernel6.2 and later · before 6.6.76
  • linux linux kernel6.7 and later · before 6.12.13
  • linux linux kernel6.13 and later · before 6.13.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.18affected
    • f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and later · before cb1de9309a48cc5b771115781eec05075fd67039affected · git
    • f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and later · before a84d511165d6ba7f331b90ae6b6ce180ec534daaaffected · git
    • f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and later · before f554bce488605d2f70e06eeab5e4d2448c813713affected · git
    • f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and later · before 1693d1fade71646a0731b6b213298cb443d186eaaffected · git
    • f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and later · before 5066293b9b7046a906eff60e3949a887ae185a43affected · git
    • before 5.18not affected · semver
    • 6.1.129 and later · up to and including 6.1.*not affected · semver
    • 6.6.76 and later · up to and including 6.6.*not affected · semver
    • 6.12.13 and later · up to and including 6.12.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.129-16.1.129-1
Debian:13linuxbefore 6.12.13-16.12.13-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-21712Feb 27, 2025 · md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime
    22Monitor
  • ← EarlierCVE-2025-21714Feb 27, 2025 · RDMA/mlx5: Fix implicit ODP use after free
    31Monitor
  • Later →CVE-2025-21718Feb 27, 2025 · net: rose: fix timer races against user threads
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1693d1fade71646a0731b6b213298cb443d186eaVendor (CNA)
Linux Linux5066293b9b7046a906eff60e3949a887ae185a43Vendor (CNA)
Linux Linuxa84d511165d6ba7f331b90ae6b6ce180ec534daaVendor (CNA)
Linux Linuxcb1de9309a48cc5b771115781eec05075fd67039Vendor (CNA)
Linux Linuxf554bce488605d2f70e06eeab5e4d2448c813713Vendor (CNA)
azl3 kernel 6.6.64.2-9 on Azure Linux 3.06.6.78.1-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.78.1-3 on Azure Linux 3.06.6.78.1-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.129-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2024-50302100 days apartHID: core: zero-initialize the report bufferKEV
    52Plan
  • CVE-2026-52989482 days apartnvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers
    39Monitor
  • CVE-2024-47685129 days apartnetfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()
    36Monitor
  • CVE-2026-53225483 days apartsctp: fix uninit-value in __sctp_rcv_asconf_lookup()
    36Monitor
  • CVE-2026-53170483 days apartaccel/ethosu: reject DMA commands with uninitialized length
    35Monitor
  • CVE-2026-43139433 days apartxfrm6: fix uninitialized saddr in xfrm6_get_saddr()
    34Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-908 · Use of Uninitialized Resource

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records