{ "schema_version": "1.6.1", "id": "RPI-CVE-2025-40043", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2025-40043" ], "published": "2025-10-28T11:50:45Z", "summary": "net: nfc: nci: Add parameter validation for packet data", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nfc: nci: Add parameter validation for packet data\n\nSyzbot reported an uninitialized value bug in nci_init_req, which was\nintroduced by commit 5aca7966d2a7 (\"Merge tag\n'perf-tools-fixes-for-v6.17-2025-09-16' of\ngit://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools\").\n\nThis bug arises due to very limited and poor input validation\nthat was done at nic_valid_size(). This validation only\nvalidates the skb->len (directly reflects size provided at the\nuserspace interface) with the length provided in the buffer\nitself (interpreted as NCI_HEADER). This leads to the processing\nof memory content at the address assuming the correct layout\nper what opcode requires there. This leads to the accesses to\nbuffer of `skb_buff->data` which is not assigned anything yet.\n\nFollowing the same silent drop of packets of invalid sizes at\n`nic_valid_size()`, add validation of the data in the respective\nhandlers and return error values in case of failure. Release\nthe skb if error values are returned from handlers in\n`nci_nft_packet` and effectively do a silent drop\n\nPossible TODO: because we silently drop the packets, the\ncall to `nci_request` will be waiting for completion of request\nand will face timeouts. These timeouts can get excessively logged\nin the dmesg. A proper handling of them may require to export\n`nci_request_cancel` (or propagate error handling from the\nnft packets handlers).", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.156", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2025-40043" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/8fcc7315a10a84264e55bb65ede10f0af20a983f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/bfdda0123dde406dbff62e7e9136037e97998a15" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/0ba68bea1e356f466ad29449938bea12f5f3711f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/74837bca0748763a77f77db47a0bdbe63b347628" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c395d1e548cc68e84584ffa2e3ca9796a78bf7b9" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9c328f54741bd5465ca1dc717c84c04242fac2e1" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T12:19:11Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.8, "cvss_v3_severity": "High", "scenario": "AV:A - The parsed data is NCI notification payload whose RF-specific and activation parameters (ATS/RATS length byte, ATR_RES length, tech-specific params) originate from the contactless peer, so an attacker with a spoofed card or NFC emulator in proximity of a phone/POS/embedded reader supplies the malformed lengths. NFC proximity is Adjacent per kernel scoring guidance (a local unprivileged N_NCI-ldisc path also exists, but is strictly lower severity).\nAC:L - The attacker directly controls the length byte versus actual payload length and can present the malformed card/frame repeatedly until the target polls it; no race, no unpredictable memory-layout precondition is required.\nPR:N - No credentials or account on the target are needed \u2014 NFC polling activates and parses the notification automatically, and on the local variant `NCIUARTSETDRIVER` in nci_uart_tty_ioctl() has no capability check at all.\nUI:N - The NFC stack polls and processes discovery/activation notifications autonomously; the attacker brings the hostile device into range and the victim performs no action.\nS:U - The over-read, the write-back in the credits handler, and the leaked data all stay within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Tens of bytes past the payload \u2014 uninitialized slab tailroom and skb_shared_info, which holds kernel pointers \u2014 are copied into nfcid1/sens_res/ATS and exported to userspace via NFC netlink attributes, yielding stale-heap and kernel-pointer disclosure usable for KASLR defeat.\nI:H - `nci_core_conn_credits_ntf_packet()` writes masked bytes back into memory beyond the validated payload for up to 10 entries and adds an out-of-bounds byte into conn_info->credits_cnt, and unvalidated data populates ndev state (nci_ver, manufact_id, remote_gb, credits), giving attacker-shapeable kernel memory/state corruption.\nA:H - Out-of-bounds slab reads can hit a redzone/adjacent object and oops (KASAN/panic_on_oops), and the commit itself notes the resulting dropped packets leave nci_request() blocking until timeout with repeated dmesg flooding, degrading the NFC stack." } } }