CVE-2025-39939

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There is no network-facing path to `zpci_get_iommu_ctrs()`.\nAC:L - Once a device uses the identity domain, the out-of-bounds access is fully deterministic \u2014 no race to win and no attacker-uninfluenceable memory layout \u2014 corrupting the same fixed 40-byte region on every `zpci_fmb_enable_device()` call and leaking it on every statistics read. Passthrough mode is a supported, documented runtime option on s390, not an obscure debug-only Kconfig.\nPR:L - The corrupting write happens automatically during normal `pci_enable_device()` at boot/driver bind with no attacker action at all, and the disclosure file is created world-readable (`S_IFREG | S_IRUGO | S_IWUSR`), so an unprivileged local user on a system with a traversable debugfs can harvest the leaked kernel global memory. No capability check gates `zpci_get_iommu_ctrs()` itself.\nUI:N - No victim action is needed; the counter reset fires on device enable and the OOB read happens on a plain file read. Nothing requires a second user to mount, open, or configure anything.\nS:U - The corruption and disclosure are confined to kernel `.data` within the kernel's own security authority \u2014 the bug mislocates statistics counters and does not alter IOMMU translation or bypass the DMA isolation boundary. Standard kernel-internal memory corruption is Unchanged scope.\nC:H - `pci_sw_counter_show()` reads 40 bytes past the end of `s390_identity_domain` and prints them verbatim to userspace, disclosing adjacent kernel global data such as `blocking_domain`'s `ops`/`owner` function-pointer and structure pointers \u2014 a direct kernel address leak defeating KASLR and exposing kernel state.\nI:H - Five `atomic64_set()` calls zero 40 bytes of adjacent kernel global memory, overwriting live control structures \u2014 at +16 past the object this lands exactly on an `iommu_domain`'s `const struct iommu_domain_ops *ops` field, nulling a function-pointer table. This is genuine kernel memory corruption of security-relevant control data, as the commit subject states.\nA:H - Zeroing adjacent globals (e.g. `blocking_domain.ops`) produces NULL-pointer dereferences in `__iommu_attach_device()` when the blocking/release domain is later attached, and KASAN reports a `global-out-of-bounds` BUG in `zpci_fmb_enable_device`. Both result in a kernel oops/panic."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/iommu/s390-iommu.c"], "versions": [{"version": "64af12c6ec3afd7d44bc8b2044eee59f98059087", "lessThan": "17a58caf3863163c4a84a218a9649be2c8061443", "status": "affected", "versionType": "git"}, {"version": "64af12c6ec3afd7d44bc8b2044eee59f98059087", "lessThan": "b3506e9bcc777ed6af2ab631c86a9990ed97b474", "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/iommu/s390-iommu.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.16.9", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17", "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": "6.16.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.17"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/17a58caf3863163c4a84a218a9649be2c8061443"}, {"url": "https://git.kernel.org/stable/c/b3506e9bcc777ed6af2ab631c86a9990ed97b474"}], "title": "iommu/s390: Fix memory corruption when using identity domain", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-39939", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:54:54.159629Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T22:02:33.574Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-39939", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:54:54.159629Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:54:55.046Z"}}], "cna": {"title": "iommu/s390: Fix memory corruption when using identity domain", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable code is s390 PCI/IOMMU infrastructure reached through local interfaces only \u2014 `pci_enable_device()` on driver bind and the debugfs `/sys/kernel/debug/pci/<dev>/statistics` file. There is no network-facing path to `zpci_get_iommu_ctrs()`.\nAC:L - Once a device uses the identity domain, the out-of-bounds access is fully deterministic \u2014 no race to win and no attacker-uninfluenceable memory layout \u2014 corrupting the same fixed 40-byte region on every `zpci_fmb_enable_device()` call and leaking it on every statistics read. Passthrough mode is a supported, documented runtime option on s390, not an obscure debug-only Kconfig.\nPR:L - The corrupting write happens automatically during normal `pci_enable_device()` at boot/driver bind with no attacker action at all, and the disclosure file is created world-readable (`S_IFREG | S_IRUGO | S_IWUSR`), so an unprivileged local user on a system with a traversable debugfs can harvest the leaked kernel global memory. No capability check gates `zpci_get_iommu_ctrs()` itself.\nUI:N - No victim action is needed; the counter reset fires on device enable and the OOB read happens on a plain file read. Nothing requires a second user to mount, open, or configure anything.\nS:U - The corruption and disclosure are confined to kernel `.data` within the kernel's own security authority \u2014 the bug mislocates statistics counters and does not alter IOMMU translation or bypass the DMA isolation boundary. Standard kernel-internal memory corruption is Unchanged scope.\nC:H - `pci_sw_counter_show()` reads 40 bytes past the end of `s390_identity_domain` and prints them verbatim to userspace, disclosing adjacent kernel global data such as `blocking_domain`'s `ops`/`owner` function-pointer and structure pointers \u2014 a direct kernel address leak defeating KASLR and exposing kernel state.\nI:H - Five `atomic64_set()` calls zero 40 bytes of adjacent kernel global memory, overwriting live control structures \u2014 at +16 past the object this lands exactly on an `iommu_domain`'s `const struct iommu_domain_ops *ops` field, nulling a function-pointer table. This is genuine kernel memory corruption of security-relevant control data, as the commit subject states.\nA:H - Zeroing adjacent globals (e.g. `blocking_domain.ops`) produces NULL-pointer dereferences in `__iommu_attach_device()` when the blocking/release domain is later attached, and KASAN reports a `global-out-of-bounds` BUG in `zpci_fmb_enable_device`. Both result in a kernel oops/panic."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "64af12c6ec3afd7d44bc8b2044eee59f98059087", "lessThan": "17a58caf3863163c4a84a218a9649be2c8061443", "versionType": "git"}, {"status": "affected", "version": "64af12c6ec3afd7d44bc8b2044eee59f98059087", "lessThan": "b3506e9bcc777ed6af2ab631c86a9990ed97b474", "versionType": "git"}], "programFiles": ["drivers/iommu/s390-iommu.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"status": "unaffected", "version": "0", "lessThan": "6.15", "versionType": "semver"}, {"status": "unaffected", "version": "6.16.9", "versionType": "semver", "lessThanOrEqual": "6.16.*"}, {"status": "unaffected", "version": "6.17", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/iommu/s390-iommu.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/17a58caf3863163c4a84a218a9649be2c8061443"}, {"url": "https://git.kernel.org/stable/c/b3506e9bcc777ed6af2ab631c86a9990ed97b474"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/s390: Fix memory corruption when using identity domain\n\nzpci_get_iommu_ctrs() returns counter information to be reported as part\nof device statistics; these counters are stored as part of the s390_domain.\nThe problem, however, is that the identity domain is not backed by an\ns390_domain and so the conversion via to_s390_domain() yields a bad address\nthat is zero'd initially and read on-demand later via a sysfs read.\nThese counters aren't necessary for the identity domain; just return NULL\nin this case.\n\nThis issue was discovered via KASAN with reports that look like:\nBUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device\nwhen using the identity domain for a device on s390."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.16.9", "versionStartIncluding": "6.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.17", "versionStartIncluding": "6.15"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:06:14.864Z"}}}, "cveMetadata": {"cveId": "CVE-2025-39939", "state": "PUBLISHED", "dateUpdated": "2026-10-15T22:02:33.574Z", "dateReserved": "2025-04-16T07:20:57.148Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-10-04T07:31:02.521Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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El problema, sin embargo, es que el dominio de identidad no est\u00e1 respaldado por un s390_domain y por lo tanto la conversi\u00f3n a trav\u00e9s de to_s390_domain() produce una direcci\u00f3n incorrecta que se pone a cero inicialmente y se lee bajo demanda m\u00e1s tarde a trav\u00e9s de una lectura de sysfs. Estos contadores no son necesarios para el dominio de identidad; simplemente devolver NULL en este caso.\n\nEste problema fue descubierto a trav\u00e9s de KASAN con informes que se ven as\u00ed:\nBUG: KASAN: global-out-of-bounds en zpci_fmb_enable_device\nal usar el dominio de identidad para un dispositivo en s390."}], "id": "CVE-2025-39939", "lastModified": "2026-10-19T21:10:00.160", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-39939", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-15T21:54:54.159629Z", "version": "2.0.3"}}]}, "published": "2025-10-04T08:15:46.860", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/17a58caf3863163c4a84a218a9649be2c8061443"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b3506e9bcc777ed6af2ab631c86a9990ed97b474"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: iommu/s390: Fix memory corruption when using identity domain", "id": "2401416", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2401416"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\niommu/s390: Fix memory corruption when using identity domain\nzpci_get_iommu_ctrs() returns counter information to be reported as part\nof device statistics; these counters are stored as part of the s390_domain.\nThe problem, however, is that the identity domain is not backed by an\ns390_domain and so the conversion via to_s390_domain() yields a bad address\nthat is zero'd initially and read on-demand later via a sysfs read.\nThese counters aren't necessary for the identity domain; just return NULL\nin this case.\nThis issue was discovered via KASAN with reports that look like:\nBUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device\nwhen using the identity domain for a device on s390."], "name": "CVE-2025-39939", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:rhivos:1", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat In-Vehicle Operating System 1"}], "public_date": "2025-10-04T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-39939\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-39939\nhttps://lore.kernel.org/linux-cve-announce/2025100418-CVE-2025-39939-7ec4@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-10-06T14:41:55.844064+00:00", "updated": "2025-10-06T14:41:55.844116+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}