{ "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-2025-39749", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-39749", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-09-11T16:52:21.228Z", "updatedAt": "2026-05-12T12:06:44.240Z", "importedAt": "2026-10-24T01:57:34.152Z", "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": "rcu: Protect ->defer_qs_iw_pending from data race", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nrcu: Protect ->defer_qs_iw_pending from data race\n\nOn kernels built with CONFIG_IRQ_WORK=y, when rcu_read_unlock() is\ninvoked within an interrupts-disabled region of code [1], it will invoke\nrcu_read_unlock_special(), which uses an irq-work handler to force the\nsystem to notice when the RCU read-side critical section actually ends.\nThat end won't happen until interrupts are enabled at the soonest.\n\nIn some kernels, such as those booted with rcutree.use_softirq=y, the\nirq-work handler is used unconditionally.\n\nThe per-CPU rcu_data structure's ->defer_qs_iw_pending field is\nupdated by the irq-work handler and is both read and updated by\nrcu_read_unlock_special(). This resulted in the following KCSAN splat:\n\n------------------------------------------------------------------------\n\nBUG: KCSAN: data-race in rcu_preempt_deferred_qs_handler / rcu_read_unlock_special\n\nread to 0xffff96b95f42d8d8 of 1 bytes by task 90 on cpu 8:\n rcu_read_unlock_special+0x175/0x260\n __rcu_read_unlock+0x92/0xa0\n rt_spin_unlock+0x9b/0xc0\n __local_bh_enable+0x10d/0x170\n __local_bh_enable_ip+0xfb/0x150\n rcu_do_batch+0x595/0xc40\n rcu_cpu_kthread+0x4e9/0x830\n smpboot_thread_fn+0x24d/0x3b0\n kthread+0x3bd/0x410\n ret_from_fork+0x35/0x40\n ret_from_fork_asm+0x1a/0x30\n\nwrite to 0xffff96b95f42d8d8 of 1 bytes by task 88 on cpu 8:\n rcu_preempt_deferred_qs_handler+0x1e/0x30\n irq_work_single+0xaf/0x160\n run_irq_workd+0x91/0xc0\n smpboot_thread_fn+0x24d/0x3b0\n kthread+0x3bd/0x410\n ret_from_fork+0x35/0x40\n ret_from_fork_asm+0x1a/0x30\n\nno locks held by irq_work/8/88.\nirq event stamp: 200272\nhardirqs last enabled at (200272): [] finish_task_switch+0x131/0x320\nhardirqs last disabled at (200271): [] __schedule+0x129/0xd70\nsoftirqs last enabled at (0): [] copy_process+0x4df/0x1cc0\nsoftirqs last disabled at (0): [<0000000000000000>] 0x0\n\n------------------------------------------------------------------------\n\nThe problem is that irq-work handlers run with interrupts enabled, which\nmeans that rcu_preempt_deferred_qs_handler() could be interrupted,\nand that interrupt handler might contain an RCU read-side critical\nsection, which might invoke rcu_read_unlock_special(). In the strict\nKCSAN mode of operation used by RCU, this constitutes a data race on\nthe ->defer_qs_iw_pending field.\n\nThis commit therefore disables interrupts across the portion of the\nrcu_preempt_deferred_qs_handler() that updates the ->defer_qs_iw_pending\nfield. This suffices because this handler is not a fast path.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "74f58f382a7c8333f8d09701aefaa25913bdbe0e" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "f937759c7432d6151b73e1393b6517661813d506" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "0ad84d62217488e679ecc90e8628980dcc003de3" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "b5de8d80b5d049f051b95d9b1ee50ae4ab656124" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "b55947b725f190396f475d5d0c59aa855a4d8895" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "e35e711c78c8a4c43330c0dcb1c4d507a19c20f4" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "90de9c94ea72327cfa9c2c9f6113c23a513af60b" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "55e11f6776798b27cf09a7aa0d718415d4fc9cf5" }, { "version": "0864f057b050bc6dd68106b3185e02db5140012d", "status": "affected", "versionType": "git", "lessThan": "90c09d57caeca94e6f3f87c49e96a91edd40cbfd" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.3", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.3" }, { "version": "5.4.297", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.241", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.190", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.149", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.103", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.43", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.15.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.15.*" }, { "version": "6.16.2", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.16.*" }, { "version": "6.17", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }