{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21810","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T08:45:45.772Z","datePublished":"2025-02-27T20:01:01.630Z","dateUpdated":"2026-08-05T11:54:37.861Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:54:37.861Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndriver core: class: Fix wild pointer dereferences in API class_dev_iter_next()\n\nThere are a potential wild pointer dereferences issue regarding APIs\nclass_dev_iter_(init|next|exit)(), as explained by below typical usage:\n\n// All members of @iter are wild pointers.\nstruct class_dev_iter iter;\n\n// class_dev_iter_init(@iter, @class, ...) checks parameter @class for\n// potential class_to_subsys() error, and it returns void type and does\n// not initialize its output parameter @iter, so caller can not detect\n// the error and continues to invoke class_dev_iter_next(@iter) even if\n// @iter still contains wild pointers.\nclass_dev_iter_init(&iter, ...);\n\n// Dereference these wild pointers in @iter here once suffer the error.\nwhile (dev = class_dev_iter_next(&iter)) { ... };\n\n// Also dereference these wild pointers here.\nclass_dev_iter_exit(&iter);\n\nActually, all callers of these APIs have such usage pattern in kernel tree.\nFix by:\n- Initialize output parameter @iter by memset() in class_dev_iter_init()\n  and give callers prompt by pr_crit() for the error.\n- Check if @iter is valid in class_dev_iter_next()."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Every affected consumer of class_dev_iter_*() is reached through local interfaces — `/proc/diskstats` and `/proc/partitions` (disk_seqf_start), cgroup `io.stat` (blkcg_fill_root_iostats), and the NFC generic-netlink `NFC_CMD_GET_DEVICE` dump. There is no remote or adjacent-network consumer of this driver-core API.\nAC:L - Once the code path is entered the wild dereference is deterministic, and the attacker controls the memory that becomes the iterator: on the two most reachable paths the iterator is a plain unzeroed `kmalloc(32)` object, so an unprivileged process can pre-spray `kmalloc-32` with chosen bytes and repeat the triggering read/dump arbitrarily often until the layout lands.\nPR:L - `/proc/diskstats`, `/proc/partitions` and cgroup `io.stat` are world-readable, and the NFC `NFC_CMD_GET_DEVICE` dumpit entry in `nfc_genl_ops[]` is one of the few NFC operations with no `GENL_ADMIN_PERM` flag — so an ordinary unprivileged local user reaches `class_dev_iter_next()` with no capability of any kind.\nUI:N - The attacker triggers the path entirely on their own by reading a procfs file or issuing a netlink dump; no victim action, mount, or device plug-in is involved.\nS:U - The corruption and any resulting code execution stay within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `klist_next()` dereferences the uninitialized `i_klist` and walks `k_list`/`n_node` links, giving an attacker-directed read of arbitrary kernel memory that is then reflected through the iteration; combined with the call gadget this yields full memory disclosure.\nI:H - The uninitialized iterator drives `spin_lock_irqsave()` on a controlled address, a `kref_put`/`list_del` write pair in `klist_dec_and_del()`, and finally an indirect call `put(last)` through a function pointer read from attacker-groomable memory — an arbitrary-write and control-flow-hijack primitive.\nA:H - Even without successful grooming, dereferencing wild pointers in `klist_next()`/`klist_iter_exit()`/`subsys_put()` reliably produces a kernel oops or panic, and it happens while holding a spinlock with interrupts disabled."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/class.c"],"versions":[{"version":"7b884b7f24b42fa25e92ed724ad82f137610afaf","lessThan":"f4b9bc823b0cfdebfed479c0e87d6939c7562e87","status":"affected","versionType":"git"},{"version":"7b884b7f24b42fa25e92ed724ad82f137610afaf","lessThan":"1614e75d1a1b63db6421c7a4bf37004720c7376c","status":"affected","versionType":"git"},{"version":"7b884b7f24b42fa25e92ed724ad82f137610afaf","lessThan":"5c504e9767b947cf7d4e29b811c0c8b3c53242b7","status":"affected","versionType":"git"},{"version":"7b884b7f24b42fa25e92ed724ad82f137610afaf","lessThan":"e128f82f7006991c99a58114f70ef61e937b1ac1","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/base/class.c"],"versions":[{"version":"6.4","status":"affected"},{"version":"0","lessThan":"6.4","status":"unaffected","versionType":"semver"},{"version":"6.6.76","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.13","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.2","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14","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":"6.4","versionEndExcluding":"6.6.76"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.12.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.13.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f4b9bc823b0cfdebfed479c0e87d6939c7562e87"},{"url":"https://git.kernel.org/stable/c/1614e75d1a1b63db6421c7a4bf37004720c7376c"},{"url":"https://git.kernel.org/stable/c/5c504e9767b947cf7d4e29b811c0c8b3c53242b7"},{"url":"https://git.kernel.org/stable/c/e128f82f7006991c99a58114f70ef61e937b1ac1"}],"title":"driver core: class: Fix wild pointer dereferences in API class_dev_iter_next()","x_generator":{"engine":"bippy-1.2.0"}}}}