GHSA-76W3-FGP7-3HF7
Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-12 21:31In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()
Commit 38a6f0865796 ("net: sched: support hash selecting tx queue") added SKBEDIT_F_TXQ_SKBHASH support. The inclusive range size is computed as:
mapping_mod = queue_mapping_max - queue_mapping + 1;
The range size can be 65536 when the requested range covers all possible u16 queue IDs (e.g. queue_mapping=0 and queue_mapping_max=U16_MAX). That value cannot be represented in a u16 and previously wrapped to 0, so tcf_skbedit_hash() could trigger a divide-by-zero:
queue_mapping += skb_get_hash(skb) % params->mapping_mod;
Compute mapping_mod in a wider type and reject ranges larger than U16_MAX to prevent params->mapping_mod from becoming 0 and avoid the crash.
{
"affected": [],
"aliases": [
"CVE-2026-43238"
],
"database_specific": {
"cwe_ids": [
"CWE-369"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-06T12:16:44Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()\n\nCommit 38a6f0865796 (\"net: sched: support hash selecting tx queue\")\nadded SKBEDIT_F_TXQ_SKBHASH support. The inclusive range size is\ncomputed as:\n\nmapping_mod = queue_mapping_max - queue_mapping + 1;\n\nThe range size can be 65536 when the requested range covers all possible\nu16 queue IDs (e.g. queue_mapping=0 and queue_mapping_max=U16_MAX).\nThat value cannot be represented in a u16 and previously wrapped to 0,\nso tcf_skbedit_hash() could trigger a divide-by-zero:\n\nqueue_mapping += skb_get_hash(skb) % params-\u003emapping_mod;\n\nCompute mapping_mod in a wider type and reject ranges larger than U16_MAX\nto prevent params-\u003emapping_mod from becoming 0 and avoid the crash.",
"id": "GHSA-76w3-fgp7-3hf7",
"modified": "2026-05-12T21:31:26Z",
"published": "2026-05-06T12:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43238"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/015cebdfcb97b5347fb7f598ea712a281cb35840"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3c2b95b26860bd6f8e2310d31ea1200d3f8f173e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4ece5eb4836f8ff03b9004dc2430a7169f282851"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/59809fda4da7730cfe84a948033f47eb45db073d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c735a7d98c982a786b0db71eb6566ee00aaa04f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/be054cc66f739a9ba615dba9012a07fab8e7dd6f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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