GHSA-27VC-6RPF-73GH
Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix stale receive device on merged fragments
Fragment reassembly reuses the skb from the highest-numbered buffered fragment as the merged packet. When that fragment was received on a hard interface which is deleted before the chain completes, the merged skb can re-enter the receive path with a stale skb->dev and skb_iif.
batadv_batman_skb_recv() passes such merged packets through the normal receive handlers again. DAT and bridge loop avoidance both derive the ARP header length from skb->dev, so they can dereference the freed net_device before the packet reaches the local mesh interface.
Refresh the receive device metadata from the current receive device before running the packet handlers. This keeps internally reinjected merged fragments consistent with the normal receive path after hard interface teardown.
{
"affected": [],
"aliases": [
"CVE-2026-89951"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T11:17:05Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: fix stale receive device on merged fragments\n\nFragment reassembly reuses the skb from the highest-numbered buffered\nfragment as the merged packet. When that fragment was received on a hard\ninterface which is deleted before the chain completes, the merged skb can\nre-enter the receive path with a stale skb-\u003edev and skb_iif.\n\nbatadv_batman_skb_recv() passes such merged packets through the normal\nreceive handlers again. DAT and bridge loop avoidance both derive the ARP\nheader length from skb-\u003edev, so they can dereference the freed net_device\nbefore the packet reaches the local mesh interface.\n\nRefresh the receive device metadata from the current receive device before\nrunning the packet handlers. This keeps internally reinjected merged\nfragments consistent with the normal receive path after hard interface\nteardown.",
"id": "GHSA-27vc-6rpf-73gh",
"modified": "2026-09-16T15:31:03Z",
"published": "2026-09-16T12:30:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89951"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2dffc8c44b6e3347b3719c6419c07b4a18fea895"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/63d86250fa7cbe22451369bd1c0881dfc8190958"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6df64825f8b199921120c685af2abca14b077331"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a2c272da99c2077088083c14961cf2f1e4506995"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ad46c907d7d9975a285c1e89a4adde652eaa93f5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e91d2cc7441d89a45bad73ad9789159c7441cb80"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f4b4ae763b5d59319fad62a00c76676758e7dafa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f830c2dfc1431764db9256b3d5db1695fc9a7f56"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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