GHSA-4HX5-9M7X-6XGV
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link
mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree() after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents future RCU readers from obtaining the pointer -- it does not wait for existing readers that already hold it via rcu_dereference.
The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer via rcu_dereference just before the NULL assignment, it will dereference freed memory after the kfree.
struct mt76_vif_link already contains an rcu_head field that is unused at this free site -- a developer oversight, since the adjacent kfree_rcu_mightsleep call for rx_sc in the same function shows the pattern was understood.
Replace kfree(mlink) with kfree_rcu(mlink, rcu_head).
{
"affected": [],
"aliases": [
"CVE-2026-74325"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:33Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link\n\nmt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()\nafter rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents\nfuture RCU readers from obtaining the pointer -- it does not wait for\nexisting readers that already hold it via rcu_dereference.\n\nThe TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink-\u003ewcid\nand mlink-\u003eidx under rcu_read_lock. If a TX softirq obtained the pointer\nvia rcu_dereference just before the NULL assignment, it will dereference\nfreed memory after the kfree.\n\nstruct mt76_vif_link already contains an rcu_head field that is unused at\nthis free site -- a developer oversight, since the adjacent\nkfree_rcu_mightsleep call for rx_sc in the same function shows the\npattern was understood.\n\nReplace kfree(mlink) with kfree_rcu(mlink, rcu_head).",
"id": "GHSA-4hx5-9m7x-6xgv",
"modified": "2026-08-17T06:33:38Z",
"published": "2026-08-15T06:32:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74325"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/50e700ac0edce72dee5c3a9755865d9423696ac7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7fae097aa9a56c30febf539d72ef3773165d3aa3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c7a83899203ed36696a2d35ddd03c0f522874a63"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.