GHSA-PJM2-H6FG-MFW7
Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-24 18:32In the Linux kernel, the following vulnerability has been resolved:
net: usb: rtl8150: fix use-after-free in rtl8150_start_xmit()
syzbot reported a KASAN slab-use-after-free read in rtl8150_start_xmit() when accessing skb->len for tx statistics after usb_submit_urb() has been called:
BUG: KASAN: slab-use-after-free in rtl8150_start_xmit+0x71f/0x760 drivers/net/usb/rtl8150.c:712 Read of size 4 at addr ffff88810eb7a930 by task kworker/0:4/5226
The URB completion handler write_bulk_callback() frees the skb via dev_kfree_skb_irq(dev->tx_skb). The URB may complete on another CPU in softirq context before usb_submit_urb() returns in the submitter, so by the time the submitter reads skb->len the skb has already been queued to the per-CPU completion_queue and freed by net_tx_action():
CPU A (xmit) CPU B (USB completion softirq) ------------ ------------------------------ dev->tx_skb = skb; usb_submit_urb() --+ |-------> write_bulk_callback() | dev_kfree_skb_irq(dev->tx_skb) | net_tx_action() | napi_skb_cache_put() <-- free netdev->stats.tx_bytes | += skb->len; <-- UAF read
Fix it by caching skb->len before submitting the URB and using the cached value when updating the tx_bytes counter.
The pre-existing tx_bytes semantics are preserved: the counter tracks the original frame length (skb->len), not the ETH_ZLEN/USB-alignment padded "count" value that is handed to the device. Changing that would be a user-visible accounting change and is out of scope for this UAF fix.
{
"affected": [],
"aliases": [
"CVE-2026-52982"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-24T17:17:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: usb: rtl8150: fix use-after-free in rtl8150_start_xmit()\n\nsyzbot reported a KASAN slab-use-after-free read in rtl8150_start_xmit()\nwhen accessing skb-\u003elen for tx statistics after usb_submit_urb() has\nbeen called:\n\n BUG: KASAN: slab-use-after-free in rtl8150_start_xmit+0x71f/0x760\n drivers/net/usb/rtl8150.c:712\n Read of size 4 at addr ffff88810eb7a930 by task kworker/0:4/5226\n\nThe URB completion handler write_bulk_callback() frees the skb via\ndev_kfree_skb_irq(dev-\u003etx_skb). The URB may complete on another CPU\nin softirq context before usb_submit_urb() returns in the submitter,\nso by the time the submitter reads skb-\u003elen the skb has already been\nqueued to the per-CPU completion_queue and freed by net_tx_action():\n\n CPU A (xmit) CPU B (USB completion softirq)\n ------------ ------------------------------\n dev-\u003etx_skb = skb;\n usb_submit_urb() --+\n |-------\u003e write_bulk_callback()\n | dev_kfree_skb_irq(dev-\u003etx_skb)\n | net_tx_action()\n | napi_skb_cache_put() \u003c-- free\n netdev-\u003estats.tx_bytes |\n += skb-\u003elen; \u003c-- UAF read\n\nFix it by caching skb-\u003elen before submitting the URB and using the\ncached value when updating the tx_bytes counter.\n\nThe pre-existing tx_bytes semantics are preserved: the counter tracks\nthe original frame length (skb-\u003elen), not the ETH_ZLEN/USB-alignment\npadded \"count\" value that is handed to the device. Changing that\nwould be a user-visible accounting change and is out of scope for\nthis UAF fix.",
"id": "GHSA-pjm2-h6fg-mfw7",
"modified": "2026-06-24T18:32:42Z",
"published": "2026-06-24T18:32:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52982"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/23f0e34c64acba15cad4d23e50f41f533da195fa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/24831b0b2ada9fef18d1f486b7b7c444ee5ba637"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/30cf9829d09ca958279c937af8e35495cd2f1e09"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/423b5b86e14e190f6e3161eb5f2ea5f908295ba7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4dd7eb94f79486b77ca6b4c8676aedbc465dc802"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5af290c86fa81ddbc86a08d54229af5daa40c6a4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5db090ca07b28a63fb1499690cf19a3f3adafacb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6999d70e0eda39af029fa1891c48f0a8832b09d5"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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