GHSA-26X8-4CM5-WHJX
Vulnerability from github – Published: 2025-12-09 18:30 – Updated: 2025-12-09 18:30In 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: 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.
{
"affected": [],
"aliases": [
"CVE-2023-53843"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-09T16:17:24Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject negative ifindex\n\nRecent changes in net-next (commit 759ab1edb56c (\"net: store netdevs\nin an xarray\")) refactored the handling of pre-assigned ifindexes\nand let syzbot surface a latent problem in ovs. ovs does not validate\nifindex, making it possible to create netdev ports with negative\nifindex values. It\u0027s easy to repro with YNL:\n\n$ ./cli.py --spec netlink/specs/ovs_datapath.yaml \\\n --do new \\\n\t --json \u0027{\"upcall-pid\": 1, \"name\":\"my-dp\"}\u0027\n$ ./cli.py --spec netlink/specs/ovs_vport.yaml \\\n\t --do new \\\n\t --json \u0027{\"upcall-pid\": \"00000001\", \"name\": \"some-port0\", \"dp-ifindex\":3,\"ifindex\":4294901760,\"type\":2}\u0027\n\n$ ip link show\n-65536: some-port0: \u003cBROADCAST,MULTICAST\u003e mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000\n link/ether 7a:48:21:ad:0b:fb brd ff:ff:ff:ff:ff:ff\n...\n\nValidate the inputs. Now the second command correctly returns:\n\n$ ./cli.py --spec netlink/specs/ovs_vport.yaml \\\n\t --do new \\\n\t --json \u0027{\"upcall-pid\": \"00000001\", \"name\": \"some-port0\", \"dp-ifindex\":3,\"ifindex\":4294901760,\"type\":2}\u0027\n\nlib.ynl.NlError: Netlink error: Numerical result out of range\nnl_len = 108 (92) nl_flags = 0x300 nl_type = 2\n\terror: -34\textack: {\u0027msg\u0027: \u0027integer out of range\u0027, \u0027unknown\u0027: [[type:4 len:36] b\u0027\\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\u0027], \u0027bad-attr\u0027: \u0027.ifindex\u0027}\n\nAccept 0 since it used to be silently ignored.",
"id": "GHSA-26x8-4cm5-whjx",
"modified": "2025-12-09T18:30:33Z",
"published": "2025-12-09T18:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53843"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/881faff9e548a7ddfb11595be7c1c649217d27db"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a552bfa16bab4ce901ee721346a28c4e483f4066"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c965a58376146dcfdda186819462e8eb3aadef3a"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.