- —Not scoredno CVSS score yet
- 0.20%Exploitation in 30 daysEPSS · top 90% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: vhost-vdpa: protect config_ctx from being freed under the config callback vhost_vdpa_config_cb() loads v->config_ctx and signals it without taking a reference and without holding any lock: struct eventfd_ctx *config_ctx = v->config_ctx; if (config_ctx) eventfd_signal(config_ctx); VHOST_VDPA_SET_CONFIG_CALL replaces that field and drops what is normally the last reference to the old context: swap(ctx, v->config_ctx); if (ctx) eventfd_ctx_put(ctx); eventfd_ctx_put() drops the last kref and frees the context immediately, with no RCU grace period, so a callback that has already loaded the pointer goes on to dereference freed memory. The two sides share no lock: the ioctl runs under vhost_dev.mutex, while the parent invokes the callback from its own interrupt or workqueue context. This is not the reopen refcount underflow fixed by commit f6bbf0010ba0 ("vhost-vdpa: fix use-after-free of v->config_ctx"), which was about vhost_vdpa_config_put() leaving a stale pointer behind. Here the pointer is maintained correctly and it is the read side that is unprotected. With VDUSE as the parent this is reachable from userspace with access to /dev/vduse (root by default). VDUSE_DEV_INJECT_CONFIG_IRQ queues dev->inject, and vduse_dev_irq_inject() runs the callback under VDUSE's own dev->irq_lock, which vhost does not hold. vduse_dev_reset() does flush_work(&dev->inject), but VHOST_VDPA_SET_CONFIG_CALL never goes through reset, so an inject already in flight is not waited for. A process that injects config interrupts on the VDUSE fd while another thread swaps the call fd on the vhost-vdpa fd hits it in seconds: BUG: KASAN: slab-use-after-free in native_queued_spin_lock_slowpath Read of size 4 at addr ffff888107d21808 by task kworker/u17:1/2993 Workqueue: vduse-irq vduse_dev_irq_inject Call Trace: native_queued_spin_lock_slowpath+0x97/0x5b0 _raw_spin_lock_irqsave+0xd4/0xe0 eventfd_signal_mask+0x69/0x120 vhost_vdpa_config_cb+0x34/0x50 vduse_dev_irq_inject+0x46/0x60 process_one_work+0x468/0x950 Allocated by task 2992: do_eventfd+0x50/0x200 __x64_sys_eventfd2+0x2e/0x40 Freed by task 2992: eventfd_ctx_put+0xb9/0xc0 vhost_vdpa_unlocked_ioctl+0x116c/0x2190 Add a spinlock covering every access to config_ctx, so the callback either signals a context that is still alive or observes NULL, and the put happens only once no callback can reach the old value. Clearing the parent's callback before the put would not be enough: of the in-tree set_config_cb() implementations only VDUSE takes a lock, the rest store the pointer unlocked, so that would not order against an in-flight invocation.
Timeline
ID reserved
By Linux
Published
- 26 days later
· 26 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (11 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 776f395004d829bbbf18c159ed9beb517a208c71 – < 914c7cc2e3d10dddd3c5529cbe56557c9e01702a
- affected 776f395004d829bbbf18c159ed9beb517a208c71 – < bf35c8948ab7a3eaf1f724fa1e870e3f73a1749b
- affected 776f395004d829bbbf18c159ed9beb517a208c71 – < 5a075ee2398929d5cc1393666f219c35332becb1
- affected 776f395004d829bbbf18c159ed9beb517a208c71 – < f4a93f15ed1c8406ba5c8e5b28cafacb2b3bcd11
- affected 776f395004d829bbbf18c159ed9beb517a208c71 – < 62be4e3e5f5f947fbf765b914cebdc478f715d12
- affected 5.8
- unaffected < 5.8
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.111 – ≤ 6.12.*
- unaffected 6.18.53 – ≤ 6.18.*
- unaffected 7.2.7 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References5
- https://git.kernel.org/stable/c/914c7cc2e3d10dddd3c5529cbe56557c9e01702a (opens in a new tab)
- https://git.kernel.org/stable/c/bf35c8948ab7a3eaf1f724fa1e870e3f73a1749b (opens in a new tab)
- https://git.kernel.org/stable/c/5a075ee2398929d5cc1393666f219c35332becb1 (opens in a new tab)
- https://git.kernel.org/stable/c/f4a93f15ed1c8406ba5c8e5b28cafacb2b3bcd11 (opens in a new tab)
- https://git.kernel.org/stable/c/62be4e3e5f5f947fbf765b914cebdc478f715d12 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-86646 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-97992)Record last updated .