{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-23294", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-23294", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-03-25T10:26:51.946Z", "updatedAt": "2026-08-05T12:21:10.341Z", "importedAt": "2026-10-24T01:58:02.025Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "bpf: Fix race in devmap on PREEMPT_RT", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix race in devmap on PREEMPT_RT\n\nOn PREEMPT_RT kernels, the per-CPU xdp_dev_bulk_queue (bq) can be\naccessed concurrently by multiple preemptible tasks on the same CPU.\n\nThe original code assumes bq_enqueue() and __dev_flush() run atomically\nwith respect to each other on the same CPU, relying on\nlocal_bh_disable() to prevent preemption. However, on PREEMPT_RT,\nlocal_bh_disable() only calls migrate_disable() (when\nPREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable\npreemption, which allows CFS scheduling to preempt a task during\nbq_xmit_all(), enabling another task on the same CPU to enter\nbq_enqueue() and operate on the same per-CPU bq concurrently.\n\nThis leads to several races:\n\n1. Double-free / use-after-free on bq->q[]: bq_xmit_all() snapshots\n cnt = bq->count, then iterates bq->q[0..cnt-1] to transmit frames.\n If preempted after the snapshot, a second task can call bq_enqueue()\n -> bq_xmit_all() on the same bq, transmitting (and freeing) the\n same frames. When the first task resumes, it operates on stale\n pointers in bq->q[], causing use-after-free.\n\n2. bq->count and bq->q[] corruption: concurrent bq_enqueue() modifying\n bq->count and bq->q[] while bq_xmit_all() is reading them.\n\n3. dev_rx/xdp_prog teardown race: __dev_flush() clears bq->dev_rx and\n bq->xdp_prog after bq_xmit_all(). If preempted between\n bq_xmit_all() return and bq->dev_rx = NULL, a preempting\n bq_enqueue() sees dev_rx still set (non-NULL), skips adding bq to\n the flush_list, and enqueues a frame. When __dev_flush() resumes,\n it clears dev_rx and removes bq from the flush_list, orphaning the\n newly enqueued frame.\n\n4. __list_del_clearprev() on flush_node: similar to the cpumap race,\n both tasks can call __list_del_clearprev() on the same flush_node,\n the second dereferences the prev pointer already set to NULL.\n\nThe race between task A (__dev_flush -> bq_xmit_all) and task B\n(bq_enqueue -> bq_xmit_all) on the same CPU:\n\n Task A (xdp_do_flush) Task B (ndo_xdp_xmit redirect)\n ---------------------- --------------------------------\n __dev_flush(flush_list)\n bq_xmit_all(bq)\n cnt = bq->count /* e.g. 16 */\n /* start iterating bq->q[] */\n <-- CFS preempts Task A -->\n bq_enqueue(dev, xdpf)\n bq->count == DEV_MAP_BULK_SIZE\n bq_xmit_all(bq, 0)\n cnt = bq->count /* same 16! */\n ndo_xdp_xmit(bq->q[])\n /* frames freed by driver */\n bq->count = 0\n <-- Task A resumes -->\n ndo_xdp_xmit(bq->q[])\n /* use-after-free: frames already freed! */\n\nFix this by adding a local_lock_t to xdp_dev_bulk_queue and acquiring\nit in bq_enqueue() and __dev_flush(). These paths already run under\nlocal_bh_disable(), so use local_lock_nested_bh() which on non-RT is\na pure annotation with no overhead, and on PREEMPT_RT provides a\nper-CPU sleeping lock that serializes access to the bq.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "3253cb49cbad4772389d6ef55be75db1f97da910", "status": "affected", "versionType": "git", "lessThan": "6c10b019785dc282c5f45d21e4a3f468b8fd6476" }, { "version": "3253cb49cbad4772389d6ef55be75db1f97da910", "status": "affected", "versionType": "git", "lessThan": "ab1a56c9d99189aa5c6e03940d06e40ba6a28240" }, { "version": "3253cb49cbad4772389d6ef55be75db1f97da910", "status": "affected", "versionType": "git", "lessThan": "1872e75375c40add4a35990de3be77b5741c252c" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.18", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.18" }, { "version": "6.18.17", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.7", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }