GHSA-2XW4-RH62-8Q7M
Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-11 12:33In the Linux kernel, the following vulnerability has been resolved:
net/packet: defer vmalloc TX_RING free until skbs finish
AF_PACKET TX_RING skbs keep a raw pointer to their ring frame. The skb page references preserve page-backed ring blocks after pg_vec is freed, but they do not preserve a vmalloc mapping.
tpacket_destruct_skb() currently drops the pending reference before writing the timestamp and TP_STATUS_AVAILABLE to the frame. Move the decrement after those stores. The smp_wmb() in __packet_set_status() orders the frame stores before the decrement.
Also recheck pending TX frames under pg_vec_lock before non-closing ring replacement, so a racing send cannot add a pending skb between the initial check and the ring swap.
Ring allocation can produce a mixture of page-backed and vmalloc-backed blocks. Allocate deferred-work storage during TX ring setup when the first vmalloc-backed block is encountered, and keep its pointer in the pg_vec allocation header. If allocation fails, return -ENOMEM from ring setup. On socket close, a non-NULL pointer identifies a vmalloc-backed vector without a scan. If TX skbs remain, defer the whole vector to system_long_wq.
After pg_vec is detached, a late destructor can skip the pending decrement. Use socket write-memory accounting as the deferred lifetime gate instead: an skb remains charged through its final sock_wfree(), after all ring-frame accesses. The delayed work retains a socket reference and reschedules itself until no TX skbs remain.
Move pending_refcnt release to packet_sock_destruct() so late skb destructors and deferred cleanup can safely use it after packet_release(). Page-backed teardown remains synchronous, and no lock is added to the TX completion hot path.
{
"affected": [],
"aliases": [
"CVE-2026-80841"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-04T16:18:12Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: defer vmalloc TX_RING free until skbs finish\n\nAF_PACKET TX_RING skbs keep a raw pointer to their ring frame. The skb\npage references preserve page-backed ring blocks after pg_vec is freed,\nbut they do not preserve a vmalloc mapping.\n\ntpacket_destruct_skb() currently drops the pending reference before\nwriting the timestamp and TP_STATUS_AVAILABLE to the frame. Move the\ndecrement after those stores. The smp_wmb() in __packet_set_status()\norders the frame stores before the decrement.\n\nAlso recheck pending TX frames under pg_vec_lock before non-closing\nring replacement, so a racing send cannot add a pending skb between\nthe initial check and the ring swap.\n\nRing allocation can produce a mixture of page-backed and vmalloc-backed\nblocks. Allocate deferred-work storage during TX ring setup when the\nfirst vmalloc-backed block is encountered, and keep its pointer in the\npg_vec allocation header. If allocation fails, return -ENOMEM from ring\nsetup. On socket close, a non-NULL pointer identifies a vmalloc-backed\nvector without a scan. If TX skbs remain, defer the whole vector to\nsystem_long_wq.\n\nAfter pg_vec is detached, a late destructor can skip the pending\ndecrement. Use socket write-memory accounting as the deferred lifetime\ngate instead: an skb remains charged through its final sock_wfree(),\nafter all ring-frame accesses. The delayed work retains a socket\nreference and reschedules itself until no TX skbs remain.\n\nMove pending_refcnt release to packet_sock_destruct() so late skb\ndestructors and deferred cleanup can safely use it after\npacket_release(). Page-backed teardown remains synchronous, and no lock\nis added to the TX completion hot path.",
"id": "GHSA-2xw4-rh62-8q7m",
"modified": "2026-09-11T12:33:23Z",
"published": "2026-09-04T18:31:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80841"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0189dce07db2dc059ae0570e06758ec4233c6e11"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/550d00aa58193fb649a09a9c9e338c685adad784"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/992cc9f94ca924089a506ba9b327caa9af797529"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ed25ed29034ddc3dbe451ccbaa58ab9932f99d8b"
}
],
"schema_version": "1.4.0",
"severity": []
}
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.
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- 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.