{ "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//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" } } } }