CVE-2025-21972

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This avoids incorrect reassembly when packets are cloned, and\nprevents a memory leak due to circular references between fragments and\ntheir skb_shared_info.\n\nThe upcoming MCTP-over-USB driver uses skb_clone which can trigger the\nproblem - other MCTP drivers don't share SKBs.\n\nA kunit test is added to reproduce the issue."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:A - The vulnerable code is a network-stack packet handler (`ETH_P_MCTP` packet_type \u2192 `mctp_route_input`), but MCTP has no internet-routable transport in the kernel \u2014 packets arrive from a device on the local management bus (SMBus/I2C, I3C, USB, serial), a limited administrative domain directly analogous to the Bluetooth/WiFi case.\nAC:L - The attacker fully controls both preconditions: sending a multi-packet (SOM/EOM) fragmented message, and causing the skbs to be clones by packing several MCTP packets into a single transfer (`mctp-usb.c:219`). No race, memory-layout dependency, or victim state is involved, and the kunit reproducer added by the fix triggers it deterministically.\nPR:N - There is no authentication or authorization anywhere on the path from `mctp_pkttype_receive()` to `mctp_frag_queue()` \u2014 MCTP packets are parsed and reassembled purely on header contents, so a device on the bus needs no credentials or local account.\nUI:N - Reassembly happens in softirq context on packet receive; no user action is needed on the victim system beyond having MCTP configured, which is the normal state for the affected BMC/host management deployments.\nS:U - The corruption and its consequences are confined to kernel skb structures within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Writing the reassembly `frag_list` into a shared `skb_shared_info` cross-links skbs belonging to different reassembly contexts and to other subsystems (e.g. AF_PACKET clones), so a socket can be delivered a fragment chain from an unrelated message with mismatched length accounting \u2014 memory-state corruption leveragable for disclosure of data from another context.\nI:H - The bug both delivers incorrectly reassembled message content to MCTP sockets (corrupting PLDM/NVMe-MI/NC-SI management traffic) and plants an attacker-influenced skb pointer into a `skb_shared_info` owned by other subsystems, which is later dereferenced and freed by an owner that never expected a fragment list.\nA:H - Every cloned fragmented message permanently leaks its skbs and backing data buffer through the circular `frag_list`/`dataref` reference, and the attacker can repeat this without limit \u2014 driving memory exhaustion and OOM/kernel failure on the memory-constrained BMC and embedded systems where MCTP is deployed."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/mctp/route.c", "net/mctp/test/route-test.c"], "versions": [{"version": "4a992bbd365094730a31bae1e12a6ca695336d57", "lessThan": "771087069a27c35c0a9fd7cc74fe7725b189b96b", "status": "affected", "versionType": "git"}, {"version": "4a992bbd365094730a31bae1e12a6ca695336d57", "lessThan": "3d0281d0713952e8dd14d6d47e3a9c345c28a3b7", "status": "affected", "versionType": "git"}, {"version": "4a992bbd365094730a31bae1e12a6ca695336d57", "lessThan": "5c47d5bfa7b096cf8890afac32141c578583f8e0", "status": "affected", "versionType": "git"}, {"version": "4a992bbd365094730a31bae1e12a6ca695336d57", "lessThan": "f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e", "status": "affected", "versionType": "git"}, {"version": "4a992bbd365094730a31bae1e12a6ca695336d57", "lessThan": "f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/mctp/route.c", "net/mctp/test/route-test.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.20", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.13.8", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.14", "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": "5.15", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.20"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.13.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.14"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/771087069a27c35c0a9fd7cc74fe7725b189b96b"}, {"url": "https://git.kernel.org/stable/c/3d0281d0713952e8dd14d6d47e3a9c345c28a3b7"}, {"url": "https://git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0"}, {"url": "https://git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e"}, {"url": "https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc"}], "title": "net: mctp: unshare packets when reassembling", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/mctp/route.c", "net/mctp/test/route-test.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "771087069a27c35c0a9fd7cc74fe7725b189b96b", "status": "affected", "version": "4a992bbd365094730a31bae1e12a6ca695336d57", "versionType": "git"}, {"lessThan": "3d0281d0713952e8dd14d6d47e3a9c345c28a3b7", "status": "affected", "version": "4a992bbd365094730a31bae1e12a6ca695336d57", "versionType": "git"}, {"lessThan": "5c47d5bfa7b096cf8890afac32141c578583f8e0", "status": "affected", "version": "4a992bbd365094730a31bae1e12a6ca695336d57", "versionType": "git"}, {"lessThan": "f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e", "status": "affected", "version": "4a992bbd365094730a31bae1e12a6ca695336d57", "versionType": "git"}, {"lessThan": "f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc", "status": "affected", "version": "4a992bbd365094730a31bae1e12a6ca695336d57", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/mctp/route.c", "net/mctp/test/route-test.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.15"}, {"lessThan": "5.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.20", "versionType": "semver"}, {"lessThanOrEqual": "6.13.*", "status": "unaffected", "version": "6.13.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "E2FE0CCC-2753-4E67-9835-56B5FA61F48D", "versionEndExcluding": "6.12.20", "versionStartIncluding": "5.15", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "0A20D4D7-B329-4C68-B662-76062EA7DCF0", "versionEndExcluding": "6.13.8", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*", "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*", "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*", "matchCriteriaId": "66619FB8-0AAF-4166-B2CF-67B24143261D", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*", "matchCriteriaId": "D3D6550E-6679-4560-902D-AF52DCFE905B", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*", "matchCriteriaId": "45B90F6B-BEC7-4D4E-883A-9DBADE021750", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:*", "matchCriteriaId": "1759FFB7-531C-41B1-9AE1-FD3D80E0D920", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: unshare packets when reassembling\n\nEnsure that the frag_list used for reassembly isn't shared with other\npackets. This avoids incorrect reassembly when packets are cloned, and\nprevents a memory leak due to circular references between fragments and\ntheir skb_shared_info.\n\nThe upcoming MCTP-over-USB driver uses skb_clone which can trigger the\nproblem - other MCTP drivers don't share SKBs.\n\nA kunit test is added to reproduce the issue."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: mctp: paquetes no compartidos al reensamblar. Aseg\u00farese de que la lista de fragmentos utilizada para el reensamblado no se comparta con otros paquetes. Esto evita un reensamblado incorrecto al clonar paquetes y previene una fuga de memoria debido a referencias circulares entre fragmentos y su skb_shared_info. El pr\u00f3ximo controlador MCTP sobre USB utiliza skb_clone, lo que puede desencadenar el problema; otros controladores MCTP no comparten los SKB. Se ha a\u00f1adido una prueba kunit para reproducir el problema."}], "id": "CVE-2025-21972", "lastModified": "2026-10-30T13:17:55.500", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2025-04-01T16:15:28.540", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3d0281d0713952e8dd14d6d47e3a9c345c28a3b7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/771087069a27c35c0a9fd7cc74fe7725b189b96b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-401"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: net: mctp: unshare packets when reassembling", "id": "2356602", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2356602"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnet: mctp: unshare packets when reassembling\nEnsure that the frag_list used for reassembly isn't shared with other\npackets. This avoids incorrect reassembly when packets are cloned, and\nprevents a memory leak due to circular references between fragments and\ntheir skb_shared_info.\nThe upcoming MCTP-over-USB driver uses skb_clone which can trigger the\nproblem - other MCTP drivers don't share SKBs.\nA kunit test is added to reproduce the issue."], "name": "CVE-2025-21972", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not 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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-04-01T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-21972\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-21972\nhttps://lore.kernel.org/linux-cve-announce/2025040146-CVE-2025-21972-1415@gregkh/T"], "threat_severity": "Low"}

{}