CVE-2026-89571

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89571", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.726Z", "datePublished": "2026-09-11T19:44:40.328Z", "dateUpdated": "2026-10-19T08:49:04.541Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:49:04.541Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/features: bound fwctl command payload to the input buffer\n\nfwctl_cmd_rpc() copies cmd->in_len bytes into inbuf = kvzalloc(cmd->in_len)\nand passes inbuf and in_len to ->fw_rpc(). The CXL callback cxlctl_fw_rpc()\nignores in_len and never checks the user-controlled op_size against it.\n\ncxlctl_set_feature() bounds op_size only from below\n(op_size <= sizeof(feat_in->hdr)) and then reads op_size - sizeof(hdr)\nbytes from feat_in->feat_data via cxl_set_feature(). With a small in_len\nand a large op_size the first memcpy() already reads past the\nkvzalloc(in_len) buffer; the out-of-bounds bytes are placed in the mailbox\npayload and sent to the device, and a large enough op_size can walk into\nunmapped memory and oops the kernel. The Get paths pin op_size to a fixed\nsize but likewise read the input struct without checking in_len.\n\nReject, at the single dispatch point, any request whose fixed header plus\nop_size does not fit in the copied-in buffer. The lower-bound test guards\nthe subtraction and ensures op_size was copied in before it is read."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only via local ioctl(FWCTL_RPC) on /dev/fwctl/fwctlN through fwctl_fops_ioctl()->fwctl_cmd_rpc()->cxlctl_fw_rpc(); CXL features/fwctl has no network, adjacent-radio, or physical-bus entry point.\nAC:L - The attacker fully controls fwctl_rpc.in_len and fwctl_rpc_cxl.op_size; a short in_len with a large op_size, or in_len=0, deterministically over-reads the kvzalloc buffer or dereferences ZERO_SIZE_PTR. No race or attacker-uncontrollable layout is required.\nPR:L - GET commands run at FWCTL_RPC_CONFIGURATION with no capability check, and SET_FEATURE for reset-effect features needs only FWCTL_RPC_DEBUG_WRITE (no CAP_SYS_RAWIO). Per CNA fwctl precedent, /dev/fwctl access is routinely granted to management/VMM users without init-namespace root.\nUI:N - The attacker opens the fwctl device and issues the RPC ioctl themselves; no victim action such as mounting a filesystem or opening a file is required.\nS:U - The heap over-read, mailbox copy, and any oops stay inside the host kernel CXL/fwctl code. This is ordinary same-host kernel impact, not a VM escape, IOMMU bypass, or other changed-scope boundary.\nC:H - cxl_set_feature() memcpy()s attacker-chosen op_size bytes from past the kvzalloc(in_len) buffer into the CXL mailbox and to the device; that unbounded kernel-heap over-read is C:H per kernel CNA guidance, and GET_FEATURE can return stored feature data including leaked heap.\nI:N - The defect is a read-only over-read into a newly allocated mailbox buffer sent to the device; there is no kernel out-of-bounds write, use-after-free, or control-flow hijack primitive.\nA:H - A large op_size walks from the short kvzalloc buffer into unmapped memory and oopses, and in_len=0 makes kvzalloc return ZERO_SIZE_PTR so reading opcode faults; either path panics the kernel and is repeatable at will."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/cxl/core/features.c"], "versions": [{"version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "lessThan": "14d52c15d5d99477b20a2d61fe36f347080da6cd", "status": "affected", "versionType": "git"}, {"version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "lessThan": "d8957545fe96f7905791c937758ebfc1ae1e5b17", "status": "affected", "versionType": "git"}, {"version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "lessThan": "f687394af983df5660b6afae7e0d06969f3af206", "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/cxl/core/features.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "6.15", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/14d52c15d5d99477b20a2d61fe36f347080da6cd"}, {"url": "https://git.kernel.org/stable/c/d8957545fe96f7905791c937758ebfc1ae1e5b17"}, {"url": "https://git.kernel.org/stable/c/f687394af983df5660b6afae7e0d06969f3af206"}], "title": "cxl/features: bound fwctl command payload to the input buffer", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/cxl/core/features.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "14d52c15d5d99477b20a2d61fe36f347080da6cd", "status": "affected", "version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "versionType": "git"}, {"lessThan": "d8957545fe96f7905791c937758ebfc1ae1e5b17", "status": "affected", "version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "versionType": "git"}, {"lessThan": "f687394af983df5660b6afae7e0d06969f3af206", "status": "affected", "version": "eb5dfcb9e36d0e46089fec777d911313c1876fa3", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/cxl/core/features.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/features: bound fwctl command payload to the input buffer\n\nfwctl_cmd_rpc() copies cmd->in_len bytes into inbuf = kvzalloc(cmd->in_len)\nand passes inbuf and in_len to ->fw_rpc(). The CXL callback cxlctl_fw_rpc()\nignores in_len and never checks the user-controlled op_size against it.\n\ncxlctl_set_feature() bounds op_size only from below\n(op_size <= sizeof(feat_in->hdr)) and then reads op_size - sizeof(hdr)\nbytes from feat_in->feat_data via cxl_set_feature(). With a small in_len\nand a large op_size the first memcpy() already reads past the\nkvzalloc(in_len) buffer; the out-of-bounds bytes are placed in the mailbox\npayload and sent to the device, and a large enough op_size can walk into\nunmapped memory and oops the kernel. The Get paths pin op_size to a fixed\nsize but likewise read the input struct without checking in_len.\n\nReject, at the single dispatch point, any request whose fixed header plus\nop_size does not fit in the copied-in buffer. The lower-bound test guards\nthe subtraction and ensures op_size was copied in before it is read."}], "id": "CVE-2026-89571", "lastModified": "2026-10-19T09:17:53.003", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:19:41.160", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/14d52c15d5d99477b20a2d61fe36f347080da6cd"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d8957545fe96f7905791c937758ebfc1ae1e5b17"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f687394af983df5660b6afae7e0d06969f3af206"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: Out-of-bounds read in CXL features leads to denial of service", "id": "2532280", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532280"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-125", "details": ["A flaw was found in the Linux kernel's CXL (Compute Express Link) features. A local attacker could exploit an out-of-bounds read vulnerability in the `fwctl_cmd_rpc()` and `cxlctl_set_feature()` functions. This occurs when the system attempts to copy data with a small input buffer length but processes a larger, user-controlled operation size without proper validation. This can lead to reading beyond the allocated memory, causing a kernel crash and resulting in a denial of service."], "name": "CVE-2026-89571", "public_date": "2026-09-11T19:44:40Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89571\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89571\nhttps://git.kernel.org/stable/c/14d52c15d5d99477b20a2d61fe36f347080da6cd\nhttps://git.kernel.org/stable/c/d8957545fe96f7905791c937758ebfc1ae1e5b17\nhttps://git.kernel.org/stable/c/f687394af983df5660b6afae7e0d06969f3af206"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[eb5dfcb9e36d0e46089fec777d911313c1876fa3,14d52c15d5d99477b20a2d61fe36f347080da6cd)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[eb5dfcb9e36d0e46089fec777d911313c1876fa3,d8957545fe96f7905791c937758ebfc1ae1e5b17)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[eb5dfcb9e36d0e46089fec777d911313c1876fa3,f687394af983df5660b6afae7e0d06969f3af206)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T04:15:05.729994+00:00", "updated": "2026-09-15T22:00:17.598193+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}