{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72380", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.922Z", "datePublished": "2026-08-15T05:56:12.866Z", "dateUpdated": "2026-08-15T05:56:12.866Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-15T05:56:12.866Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen/pvcalls: bound backend response req_id before indexing rsp[]\n\npvcalls_front_event_handler() takes req_id directly from the\nbackend-supplied ring response and uses it to index the fixed-size\nbedata->rsp[] array for a memcpy() and a store, with no range check. A\nmalicious or buggy backend can set req_id past PVCALLS_NR_RSP_PER_RING\nand drive an out-of-bounds write past the bedata allocation.\n\nreq_id was also declared int while the wire field rsp->req_id is u32, so\na range check on the signed value alone is insufficient: a backend\nreq_id of 0xffffffff becomes -1, passes a >= PVCALLS_NR_RSP_PER_RING\ntest and indexes bedata->rsp[-1]. Declare req_id as u32 so a single\nbound covers both ends.\n\nA backend that sends an out-of-range req_id has violated the wire\nprotocol, so rather than silently dropping the response, log once and\nstop trusting the backend: set bedata->disabled. The event handler then\nignores further responses, and the request paths that wait for a\nresponse return -EIO instead of blocking forever. This mirrors the\nfatal-error handling xen-netback uses (xenvif_fatal_tx_err()).\n\nThe pvcalls frontend currently trusts its backend, so this is not a\nclassic-Xen security issue, but it matters for hardening PV frontends\nagainst malicious backends (confidential and disaggregated deployments)."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/xen/pvcalls-front.c"], "versions": [{"version": "2195046bfd69e487d9a76dc47840f15c8412840c", "lessThan": "d1297a9e2fd6ce08678b370d41bc980ca798f809", "status": "affected", "versionType": "git"}, {"version": "2195046bfd69e487d9a76dc47840f15c8412840c", "lessThan": "d33846c8dcc06b83b7acdeac1e8bfbb5c0c26cb2", "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/xen/pvcalls-front.c"], "versions": [{"version": "4.15", "status": "affected"}, {"version": "0", "lessThan": "4.15", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2-rc2", "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": "4.15", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.2-rc2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d1297a9e2fd6ce08678b370d41bc980ca798f809"}, {"url": "https://git.kernel.org/stable/c/d33846c8dcc06b83b7acdeac1e8bfbb5c0c26cb2"}], "title": "xen/pvcalls: bound backend response req_id before indexing rsp[]", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/xen/pvcalls-front.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d1297a9e2fd6ce08678b370d41bc980ca798f809", "status": "affected", "version": "2195046bfd69e487d9a76dc47840f15c8412840c", "versionType": "git"}, {"lessThan": "d33846c8dcc06b83b7acdeac1e8bfbb5c0c26cb2", "status": "affected", "version": "2195046bfd69e487d9a76dc47840f15c8412840c", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/xen/pvcalls-front.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.15"}, {"lessThan": "4.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2-rc2", "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\nxen/pvcalls: bound backend response req_id before indexing rsp[]\n\npvcalls_front_event_handler() takes req_id directly from the\nbackend-supplied ring response and uses it to index the fixed-size\nbedata->rsp[] array for a memcpy() and a store, with no range check. A\nmalicious or buggy backend can set req_id past PVCALLS_NR_RSP_PER_RING\nand drive an out-of-bounds write past the bedata allocation.\n\nreq_id was also declared int while the wire field rsp->req_id is u32, so\na range check on the signed value alone is insufficient: a backend\nreq_id of 0xffffffff becomes -1, passes a >= PVCALLS_NR_RSP_PER_RING\ntest and indexes bedata->rsp[-1]. Declare req_id as u32 so a single\nbound covers both ends.\n\nA backend that sends an out-of-range req_id has violated the wire\nprotocol, so rather than silently dropping the response, log once and\nstop trusting the backend: set bedata->disabled. The event handler then\nignores further responses, and the request paths that wait for a\nresponse return -EIO instead of blocking forever. This mirrors the\nfatal-error handling xen-netback uses (xenvif_fatal_tx_err()).\n\nThe pvcalls frontend currently trusts its backend, so this is not a\nclassic-Xen security issue, but it matters for hardening PV frontends\nagainst malicious backends (confidential and disaggregated deployments)."}], "id": "CVE-2026-72380", "lastModified": "2026-08-15T06:22:11.493", "metrics": {}, "published": "2026-08-15T06:22:11.493", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d1297a9e2fd6ce08678b370d41bc980ca798f809"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d33846c8dcc06b83b7acdeac1e8bfbb5c0c26cb2"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{}