{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39994","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.150Z","datePublished":"2025-10-15T07:58:19.503Z","dateUpdated":"2026-08-05T12:06:59.351Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:06:59.351Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: tuner: xc5000: Fix use-after-free in xc5000_release\n\nThe original code uses cancel_delayed_work() in xc5000_release(), which\ndoes not guarantee that the delayed work item timer_sleep has fully\ncompleted if it was already running. This leads to use-after-free scenarios\nwhere xc5000_release() may free the xc5000_priv while timer_sleep is still\nactive and attempts to dereference the xc5000_priv.\n\nA typical race condition is illustrated below:\n\nCPU 0 (release thread)                 | CPU 1 (delayed work callback)\nxc5000_release()                       | xc5000_do_timer_sleep()\n  cancel_delayed_work()                |\n  hybrid_tuner_release_state(priv)     |\n    kfree(priv)                        |\n                                       |   priv = container_of() // UAF\n\nReplace cancel_delayed_work() with cancel_delayed_work_sync() to ensure\nthat the timer_sleep is properly canceled before the xc5000_priv memory\nis deallocated.\n\nA deadlock concern was considered: xc5000_release() is called in a process\ncontext and is not holding any locks that the timer_sleep work item might\nalso need. Therefore, the use of the _sync() variant is safe here.\n\nThis bug was initially identified through static analysis.\n\n[hverkuil: fix typo in Subject: tunner -> tuner]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","baseScore":7.3,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Both halves are software-local: the attacker arms the 5-second `timer_sleep` work through the local `/dev/dvb/adapterN/frontend0` or `/dev/videoN` device node, and the freeing `dvb_frontend_detach()` path is entered by a local write to `/sys/bus/pci/devices/<dev>/remove`/`unbind` or `rmmod` on the PCIe xc5000 cards (cx23885, cx88, saa7134), with no network, adjacent-network, or remote-peer data path into `xc5000_release()`.\nAC:L - The attacker fully controls the arming side with deterministic timing — `dvb_shutdown_timeout` defaults to 0, so closing the frontend immediately triggers `xc5000_sleep()` and the work fires exactly 5 s later — and the callback then executes for roughly 350 ms on cx231xx boards (`msleep(10)+msleep(330)+msleep(10)` in `cx231xx_tuner_callback()`), an enormous window that can be re-armed indefinitely for free; once it is hit, `cancel_delayed_work()` cannot steal a running work item and the use-after-free is unconditional.\nPR:L - Arming the vulnerable work requires nothing more than opening and closing the DVB frontend or V4L2 video node, which systemd tags with `uaccess` (and which is group `video` on media appliances, set-top boxes and DVR/kiosk systems), so an ordinary unprivileged local account suffices; no capability, user namespace, or root is needed on the attacker-controlled side.\nUI:R - Completing the exploit needs the free itself, which only occurs on driver teardown — an administrator running `rmmod`/`unbind`, or a user unplugging the USB TV tuner — an action the unprivileged attacker cannot perform, so a separate user must act while the primed work is executing.\nS:U - The corruption is confined to kernel heap objects (the freed `struct xc5000_priv` and whatever reclaims its kmalloc-192 slot) within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `xc5000_do_timer_sleep()` reads `priv->fe` out of the freed slab and `xc5000_tuner_reset()` then dereferences `fe->dvb`, `fe->dvb->priv` and `priv->i2c_props.adap->algo_data`, so spraying the kmalloc-192 cache turns the dangling pointer into an arbitrary-address read chain and leaks kernel pointers that defeat KASLR.\nI:H - `xc5000_tuner_reset()` performs `fe->callback(...)` where `fe` was loaded from the freed object, giving a fully attacker-controlled indirect call with a controlled first argument once the slab is reclaimed — a direct control-flow hijack primitive, not merely a stray read.\nA:H - Dereferencing the freed `xc5000_priv` from workqueue context reliably produces a KASAN slab-use-after-free splat and an oops/panic (and the bogus function-pointer call faults in kernel context), taking the system down."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/tuners/xc5000.c"],"versions":[{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"bc4ffd962ce16a154c44c68853b9d93f5b6fc4b8","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"e2f5eaafc0306a76fb1cb760aae804b065b8a341","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"3f876cd47ed8bca1e28d68435845949f51f90703","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"df0303b4839520b84d9367c2fad65b13650a4d42","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"71ed8b81a4906cb785966910f39cf7f5ad60a69e","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"effb1c19583bca7022fa641a70766de45c6d41ac","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"9a00de20ed8ba90888479749b87bc1532cded4ce","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"4266f012806fc18e46da4a04d130df59a4946f93","status":"affected","versionType":"git"},{"version":"f7a27ff1fb77e114d1059a5eb2ed1cffdc508ce8","lessThan":"40b7a19f321e65789612ebaca966472055dab48c","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/tuners/xc5000.c"],"versions":[{"version":"3.16","status":"affected"},{"version":"0","lessThan":"3.16","status":"unaffected","versionType":"semver"},{"version":"5.4.301","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.246","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.195","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.156","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.111","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.51","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.16.11","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17.1","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"5.4.301"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"5.10.246"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"5.15.195"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.1.156"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.6.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.12.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.16.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.17.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bc4ffd962ce16a154c44c68853b9d93f5b6fc4b8"},{"url":"https://git.kernel.org/stable/c/e2f5eaafc0306a76fb1cb760aae804b065b8a341"},{"url":"https://git.kernel.org/stable/c/3f876cd47ed8bca1e28d68435845949f51f90703"},{"url":"https://git.kernel.org/stable/c/df0303b4839520b84d9367c2fad65b13650a4d42"},{"url":"https://git.kernel.org/stable/c/71ed8b81a4906cb785966910f39cf7f5ad60a69e"},{"url":"https://git.kernel.org/stable/c/effb1c19583bca7022fa641a70766de45c6d41ac"},{"url":"https://git.kernel.org/stable/c/9a00de20ed8ba90888479749b87bc1532cded4ce"},{"url":"https://git.kernel.org/stable/c/4266f012806fc18e46da4a04d130df59a4946f93"},{"url":"https://git.kernel.org/stable/c/40b7a19f321e65789612ebaca966472055dab48c"}],"title":"media: tuner: xc5000: Fix use-after-free in xc5000_release","x_generator":{"engine":"bippy-1.2.0"}}}}