GHSA-C5MP-X9X5-3G5V
Vulnerability from github – Published: 2026-04-03 18:31 – Updated: 2026-04-03 18:31In the Linux kernel, the following vulnerability has been resolved:
io_uring/poll: fix multishot recv missing EOF on wakeup race
When a socket send and shutdown() happen back-to-back, both fire wake-ups before the receiver's task_work has a chance to run. The first wake gets poll ownership (poll_refs=1), and the second bumps it to 2. When io_poll_check_events() runs, it calls io_poll_issue() which does a recv that reads the data and returns IOU_RETRY. The loop then drains all accumulated refs (atomic_sub_return(2) -> 0) and exits, even though only the first event was consumed. Since the shutdown is a persistent state change, no further wakeups will happen, and the multishot recv can hang forever.
Check specifically for HUP in the poll loop, and ensure that another loop is done to check for status if more than a single poll activation is pending. This ensures we don't lose the shutdown event.
{
"affected": [],
"aliases": [
"CVE-2026-23473"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-03T16:16:35Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/poll: fix multishot recv missing EOF on wakeup race\n\nWhen a socket send and shutdown() happen back-to-back, both fire\nwake-ups before the receiver\u0027s task_work has a chance to run. The first\nwake gets poll ownership (poll_refs=1), and the second bumps it to 2.\nWhen io_poll_check_events() runs, it calls io_poll_issue() which does a\nrecv that reads the data and returns IOU_RETRY. The loop then drains all\naccumulated refs (atomic_sub_return(2) -\u003e 0) and exits, even though only\nthe first event was consumed. Since the shutdown is a persistent state\nchange, no further wakeups will happen, and the multishot recv can hang\nforever.\n\nCheck specifically for HUP in the poll loop, and ensure that another\nloop is done to check for status if more than a single poll activation\nis pending. This ensures we don\u0027t lose the shutdown event.",
"id": "GHSA-c5mp-x9x5-3g5v",
"modified": "2026-04-03T18:31:22Z",
"published": "2026-04-03T18:31:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23473"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0f4ce79b8db7b040373fc664c8bc6c5fd74bd196"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a68ed2df72131447d131531a08fe4dfcf4fa4653"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bf33554b6abf7e7faeadd8af1b82037ea755a6bb"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
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.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- 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.