GHSA-24M2-RCHH-H2MX
Vulnerability from github – Published: 2026-06-08 18:31 – Updated: 2026-07-08 15:31In the Linux kernel, the following vulnerability has been resolved:
drm/v3d: Reject empty multisync extension to prevent infinite loop
v3d_get_extensions() walks a userspace-provided singly-linked list of ioctl extensions without any bound on the chain length. A local user can craft a self-referential extension (ext->next == &ext) with zero in_sync_count and out_sync_count, which bypasses the existing duplicate- extension guard:
if (se->in_sync_count || se->out_sync_count)
return -EINVAL;
The guard never fires because v3d_get_multisync_post_deps() returns immediately when count is zero, leaving both fields at zero on every iteration. The result is an infinite loop in kernel context, blocking the calling thread and pegging a CPU core indefinitely.
Fix this by rejecting a multisync extension where both in_sync_count and out_sync_count are zero in v3d_get_multisync_submit_deps(). An empty multisync carries no synchronization information and serves no useful purpose, so returning -EINVAL for such an extension is the correct defense against this attack vector.
{
"affected": [],
"aliases": [
"CVE-2026-46314"
],
"database_specific": {
"cwe_ids": [
"CWE-835"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-08T17:16:50Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/v3d: Reject empty multisync extension to prevent infinite loop\n\nv3d_get_extensions() walks a userspace-provided singly-linked list of\nioctl extensions without any bound on the chain length. A local user\ncan craft a self-referential extension (ext-\u003enext == \u0026ext) with zero\nin_sync_count and out_sync_count, which bypasses the existing duplicate-\nextension guard:\n\n if (se-\u003ein_sync_count || se-\u003eout_sync_count)\n return -EINVAL;\n\nThe guard never fires because v3d_get_multisync_post_deps() returns\nimmediately when count is zero, leaving both fields at zero on every\niteration. The result is an infinite loop in kernel context, blocking\nthe calling thread and pegging a CPU core indefinitely.\n\nFix this by rejecting a multisync extension where both in_sync_count\nand out_sync_count are zero in v3d_get_multisync_submit_deps(). An\nempty multisync carries no synchronization information and serves no\nuseful purpose, so returning -EINVAL for such an extension is the\ncorrect defense against this attack vector.",
"id": "GHSA-24m2-rchh-h2mx",
"modified": "2026-07-08T15:31:37Z",
"published": "2026-06-08T18:31:53Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46314"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/309abbddeca0c12714721928a819ef45e5710998"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4fa42a249e8cd6ed17aea04e5695b6e9001f2433"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c5164781cb388d219d8f49fa0f0b04cf86ad544"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fb44d589bf3148e13452185a6e772a7efbf2d684"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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