{"id":"CVE-2021-47152","state":"PUBLISHED","title":"mptcp: fix data stream corruption","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix data stream corruption\n\nMaxim reported several issues when forcing a TCP transparent proxy\nto use the MPTCP protocol for the inbound connections. He also\nprovided a clean reproducer.\n\nThe problem boils down to 'mptcp_frag_can_collapse_to()' assuming\nthat only MPTCP will use the given page_frag.\n\nIf others - e.g. the plain TCP protocol - allocate page fragments,\nwe can end-up re-using already allocated memory for mptcp_data_frag.\n\nFix the issue ensuring that the to-be-expanded data fragment is\nlocated at the current page frag end.\n\nv1 -> v2:\n - added missing fixes tag (Mat)","publishedAt":"2024-03-25T09:07:47.235Z","updatedAt":"2026-08-05T08:46:20.724Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"3267a061096efc91eda52c2a0c61ba76e46e4b34","versionType":"git"},{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"18e7f0580da15cac1e79d73683ada5a9e70980f8","versionType":"git"},{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"29249eac5225429b898f278230a6ca2baa1ae154","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.42","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.9","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"]}],"references":["https://git.kernel.org/stable/c/3267a061096efc91eda52c2a0c61ba76e46e4b34","https://git.kernel.org/stable/c/18e7f0580da15cac1e79d73683ada5a9e70980f8","https://git.kernel.org/stable/c/29249eac5225429b898f278230a6ca2baa1ae154"],"weaknesses":[],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47152.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47152","state":"PUBLISHED","datePublished":"2024-03-25T09:07:47.235Z","dateUpdated":"2026-08-05T08:46:20.724Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-03-04T18:12:48.846Z"},"containers":{"cna":{"title":"mptcp: fix data stream corruption","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix data stream corruption\n\nMaxim reported several issues when forcing a TCP transparent proxy\nto use the MPTCP protocol for the inbound connections. He also\nprovided a clean reproducer.\n\nThe problem boils down to 'mptcp_frag_can_collapse_to()' assuming\nthat only MPTCP will use the given page_frag.\n\nIf others - e.g. the plain TCP protocol - allocate page fragments,\nwe can end-up re-using already allocated memory for mptcp_data_frag.\n\nFix the issue ensuring that the to-be-expanded data fragment is\nlocated at the current page frag end.\n\nv1 -> v2:\n - added missing fixes tag (Mat)"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"3267a061096efc91eda52c2a0c61ba76e46e4b34","versionType":"git"},{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"18e7f0580da15cac1e79d73683ada5a9e70980f8","versionType":"git"},{"version":"18b683bff89d46ace55f12d00c0440d44d6160c4","status":"affected","lessThan":"29249eac5225429b898f278230a6ca2baa1ae154","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.42","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.9","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/mptcp/protocol.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3267a061096efc91eda52c2a0c61ba76e46e4b34"},{"url":"https://git.kernel.org/stable/c/18e7f0580da15cac1e79d73683ada5a9e70980f8"},{"url":"https://git.kernel.org/stable/c/29249eac5225429b898f278230a6ca2baa1ae154"}],"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 bug is in mptcp_sendmsg’s page_frag collapse/carve logic, reached via local sendmsg/sendto on an MPTCP socket (syscall path), not by parsing unsolicited received packets.\nAC:L - An unprivileged attacker who opens MPTCP (and/or TCP) sockets in one process fully controls shared current->task_frag interleaving and can reliably force the false collapse and overlapping reuse; no victim-only timing or layout is required.\nPR:L - Creating IPPROTO_MPTCP sockets needs only net.mptcp.enabled (default on when CONFIG_MPTCP is built); no CAP_NET_ADMIN or init-namespace root is required along the send path.\nUI:N - The attacker triggers the vulnerable sendmsg path themselves on their own sockets; no separate victim action is required.\nS:U - Impact is kernel memory/list corruption and DoS within the same host OS authority—standard local kernel compromise, not a VM/IOMMU/sandbox boundary cross.\nC:H - False collapse lets attacker-controlled send data overwrite in-page mptcp_data_frag fields (page/offset/list); corrupted frags can then be transmitted via tcp_build_frag, and the heap/list corruption is further leverageable for disclosure.\nI:H - Overlapping writes corrupt adjacent mptcp_data_frag list_head and related state (CWE-787), enabling list_add/list_del corruption and arbitrary-write primitives as seen in the reported list_add BUG paths.\nA:H - The same corruption produced kernel BUG_ON list_add/list_del failures, soft lockups at 100% CPU, and host hangs/panics in the documented reproducer."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T08:46:20.724Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.10.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.12.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.13"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/3267a061096efc91eda52c2a0c61ba76e46e4b34","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/18e7f0580da15cac1e79d73683ada5a9e70980f8","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/29249eac5225429b898f278230a6ca2baa1ae154","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T05:24:39.850Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2021-47152","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T15:54:51.146188Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-09-11T17:33:55.837Z"}}]}}}