In the Linux kernel, the following vulnerability has been resolved:

net: openvswitch: reject negative ifindex

Recent changes in net-next (commit 759ab1edb56c ("net: store netdevs
in an xarray")) refactored the handling of pre-assigned ifindexes
and let syzbot surface a latent problem in ovs. ovs does not validate
ifindex, making it possible to create netdev ports with negative
ifindex values. It's easy to repro with YNL:

$ ./cli.py --spec netlink/specs/ovs_datapath.yaml \
--do new \
--json '{"upcall-pid": 1, "name":"my-dp"}'
$ ./cli.py --spec netlink/specs/ovs_vport.yaml \
--do new \
--json '{"upcall-pid": "00000001", "name": "some-port0", "dp-ifindex":3,"ifindex":4294901760,"type":2}'

$ ip link show
-65536: some-port0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 7a:48:21:ad:0b:fb brd ff:ff:ff:ff:ff:ff
...

Validate the inputs. Now the second command correctly returns:

$ ./cli.py --spec netlink/specs/ovs_vport.yaml \
--do new \
--json '{"upcall-pid": "00000001", "name": "some-port0", "dp-ifindex":3,"ifindex":4294901760,"type":2}'

lib.ynl.NlError: Netlink error: Numerical result out of range
nl_len = 108 (92) nl_flags = 0x300 nl_type = 2
error: -34 extack: {'msg': 'integer out of range', 'unknown': [[type:4 len:36] b'\x0c\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x03\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x08\x00\x01\x00\x08\x00\x00\x00'], 'bad-attr': '.ifindex'}

Accept 0 since it used to be silently ignored.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00025.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
54c4ef34c4b6f9720fded620e2893894f9f2c554 affected < c965a58376146dcfdda186819462e8eb3aadef3a
54c4ef34c4b6f9720fded620e2893894f9f2c554 affected < 881faff9e548a7ddfb11595be7c1c649217d27db
54c4ef34c4b6f9720fded620e2893894f9f2c554 affected < a552bfa16bab4ce901ee721346a28c4e483f4066
Linux Linux affected
Version Status Constraints
6.1 affected —
0 unaffected < 6.1
6.1.47 unaffected ≤ 6.1.*
6.4.12 unaffected ≤ 6.4.*
6.5 unaffected ≤ *

No data.

No data.

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/881faff9e548a7ddfb11595be7c1c649217d27db cve-icon cve-icon
https://git.kernel.org/stable/c/a552bfa16bab4ce901ee721346a28c4e483f4066 cve-icon cve-icon
https://git.kernel.org/stable/c/c965a58376146dcfdda186819462e8eb3aadef3a cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025120958-CVE-2023-53843-195d@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2023-53843 cve-icon
https://www.cve.org/CVERecord?id=CVE-2023-53843 cve-icon
History

Wed, 10 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Tue, 09 Dec 2025 02:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject negative ifindex Recent changes in net-next (commit 759ab1edb56c ("net: store netdevs in an xarray")) refactored the handling of pre-assigned ifindexes and let syzbot surface a latent problem in ovs. ovs does not validate ifindex, making it possible to create netdev ports with negative ifindex values. It's easy to repro with YNL: $ ./cli.py --spec netlink/specs/ovs_datapath.yaml \ --do new \ --json '{"upcall-pid": 1, "name":"my-dp"}' $ ./cli.py --spec netlink/specs/ovs_vport.yaml \ --do new \ --json '{"upcall-pid": "00000001", "name": "some-port0", "dp-ifindex":3,"ifindex":4294901760,"type":2}' $ ip link show -65536: some-port0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 7a:48:21:ad:0b:fb brd ff:ff:ff:ff:ff:ff ... Validate the inputs. Now the second command correctly returns: $ ./cli.py --spec netlink/specs/ovs_vport.yaml \ --do new \ --json '{"upcall-pid": "00000001", "name": "some-port0", "dp-ifindex":3,"ifindex":4294901760,"type":2}' lib.ynl.NlError: Netlink error: Numerical result out of range nl_len = 108 (92) nl_flags = 0x300 nl_type = 2 error: -34 extack: {'msg': 'integer out of range', 'unknown': [[type:4 len:36] b'\x0c\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x03\x00\xff\xff\xff\x7f\x00\x00\x00\x00\x08\x00\x01\x00\x08\x00\x00\x00'], 'bad-attr': '.ifindex'} Accept 0 since it used to be silently ignored.
Title net: openvswitch: reject negative ifindex
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-09T01:30:05.698Z

Reserved: 2025-12-09T01:27:17.826Z

Link: CVE-2023-53843

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-09T16:17:24.613

Modified: 2025-12-09T18:37:13.640

Link: CVE-2023-53843

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-09T00:00:00Z

Links: CVE-2023-53843 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.