{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80545", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.765Z", "datePublished": "2026-08-26T14:37:16.956Z", "dateUpdated": "2026-10-15T10:09:36.505Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-15T10:09:36.505Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/zcrypt: Improve EP11 CPRB length and overflow checks\n\nThe xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input\nvalidation, creating security vulnerabilities:\n1. Missing minimum size validation: The ep11_cprb structure and\n subsequent payload fields (pld_tag, pld_lenfmt) are copied from\n userspace without verifying sufficient buffer length.\n2. Arithmetic overflow in length calculations: CEIL4 alignment could\n overflow, bypassing size checks and enabling buffer overflows.\n3. The payload is asn1 encoded but the function just uses a simple c\n struct overlay to access some fields of the payload.\n\nFix by using size_t for length calculations, adding U32_MAX boundary\nchecks after alignment, and validating minimum request size and\nminimum reply size before copying from userspace. Do a very simple\nasn1 parsing of the payload up to the function value field." } ], "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 - The flaw is reached only via local ioctl(ZSENDEP11CPRB) on /dev/z90crypt or administrator-created zcdn device nodes on IBM Z systems with EP11 crypto hardware; there is no network, Bluetooth, or USB packet path to this code.\nAC:L - The attacker fully controls ep11_urb req_len, req, and resp_len in the ioctl argument; near-SIZE_MAX lengths can wrap CEIL4 sum checks to bypass bufsize validation and trigger deterministic heap corruption without races or external timing dependencies.\nPR:L - Exploitation requires opening a zcrypt device and passing zcrypt_check_ioctl, access routinely delegated to non-root application/service accounts via zcdn nodes on shared IBM Z cloud, LPAR, and container deployments that grant EP11 CPRB ioctl permissions.\nUI:N - Triggering is self-contained by submitting a crafted EP11 request block through ioctl; no victim interaction, file opening by another user, or administrative action beyond having zcrypt device access is required.\nS:U - Impact is kernel heap corruption and privilege escalation within the same Linux security authority on the s390 host; it does not cross VM, IOMMU, or container sandbox boundaries to affect a separate security domain.\nC:H - Undersized copies leave uninitialized kmalloc data readable via struct overlays on pld_lenfmt and payload_hdr, while integer-overflowed req_len values enable copy_from_user far beyond the ap_msg buffer, providing arbitrary kernel memory disclosure primitives.\nI:H - Missing minimum-size and U32_MAX boundary checks let attacker-controlled lengths bypass ap_msg->len validation and corrupt adjacent kmalloc objects in the crypto message buffer, enabling heap control primitives and potential arbitrary kernel code execution.\nA:H - Heap buffer overflow and out-of-bounds parsing of EP11 CPRB payloads can cause kernel oops, panic, or denial of crypto services on mission-critical IBM Z systems; memory corruption alone threatens host availability even before full exploitation." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/crypto/zcrypt_msgtype6.c" ], "versions": [ { "version": "20b0b0159390fa5c00a435195649680fefda81e0", "lessThan": "f463f474773aa49ed1d6087d95d44cea7099fdc7", "status": "affected", "versionType": "git" }, { "version": "e2c6d91eb8b1533753755f07803e47eceed263d0", "lessThan": "2976b9d2e716c7e5487ca7c29a7bd076cf9adf08", "status": "affected", "versionType": "git" }, { "version": "e2c6d91eb8b1533753755f07803e47eceed263d0", "lessThan": "17ac0bc866fc624cd05f022dcd8b730c0af11bb1", "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/s390/crypto/zcrypt_msgtype6.c" ], "versions": [ { "version": "7.1", "status": "affected" }, { "version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.10", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "7.1", "versionEndExcluding": "7.1.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f463f474773aa49ed1d6087d95d44cea7099fdc7" }, { "url": "https://git.kernel.org/stable/c/2976b9d2e716c7e5487ca7c29a7bd076cf9adf08" }, { "url": "https://git.kernel.org/stable/c/17ac0bc866fc624cd05f022dcd8b730c0af11bb1" } ], "title": "s390/zcrypt: Improve EP11 CPRB length and overflow checks", "x_generator": { "engine": "bippy-1.2.0" } } } }