{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21638", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.727Z", "datePublished": "2025-01-19T10:17:56.084Z", "dateUpdated": "2026-08-05T11:53:18.276Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:53:18.276Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: sysctl: auth_enable: avoid using current->nsproxy\n\nAs mentioned in a previous commit of this series, using the 'net'\nstructure via 'current' is not recommended for different reasons:\n\n- Inconsistency: getting info from the reader's/writer's netns vs only\n from the opener's netns.\n\n- current->nsproxy can be NULL in some cases, resulting in an 'Oops'\n (null-ptr-deref), e.g. when the current task is exiting, as spotted by\n syzbot [1] using acct(2).\n\nThe 'net' structure can be obtained from the table->data using\ncontainer_of().\n\nNote that table->data could also be used directly, but that would\nincrease the size of this fix, while 'sctp.ctl_sock' still needs to be\nretrieved from 'net' structure." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Despite living in net/sctp/, `proc_sctp_do_auth()` is a procfs sysctl ->proc_handler that no received SCTP packet, socket, or association path ever invokes; it is reached only through local file I/O on /proc/sys/net/sctp/auth_enable and local syscalls (write(2), acct(2)).\nAC:L - Both trigger paths are fully deterministic and entirely attacker-scripted — unshare/open/SCM_RIGHTS/write for the netns-confusion path, or acct(2) plus lazy umount plus process exit for the NULL deref — with no race, no victim state, and no memory-layout dependency.\nPR:L - An unprivileged local user reaches the flaw via unprivileged user namespaces (default-enabled on Ubuntu/Debian/Fedora/Android), since cap_capable() grants the owner of a child user namespace CAP_NET_ADMIN over it (security/commoncap.c:92), letting a process still in the init netns write through the child's sysctl fd and have the handler act on init_net; only the secondary acct(2) oops path additionally needs CAP_SYS_PACCT.\nUI:N - The attacker performs every step from its own cooperating processes — namespace creation, fd passing, the write, or acct(2) and its own exit — with no action required from any other user or administrator.\nS:U - The flawed code and the affected resources are both kernel network-namespace state under the same kernel security authority; per kernel CNA convention namespace boundary crossings inside the kernel are scored Unchanged, and no hypervisor, IOMMU, or VM boundary is involved.\nC:N - The NULL+0x28 dereference faults before any data is returned to userspace, and the read side of the netns confusion only reports the caller's own netns value for a world-readable (0644) setting, so no protected information is disclosed.\nI:H - The netns confusion lets an unprivileged local user write init_net.sctp.auth_enable and directly mutate the host control socket's endpoint (sctp_sk(net->sctp.ctl_sock)->ep->auth_enable); clearing it makes every newly created host endpoint skip sctp_auth_init() and stop negotiating RFC 4895 AUTH, disabling SCTP chunk authentication host-wide — an attacker-chosen modification of protected host state and a bypass of a security control.\nA:H - The NULL-ptr-deref oopses inside do_exit() after exit_task_namespaces() while acct->lock is held under mnt_pin_kill(), wedging the task mid-teardown with a permanently held mutex and pinned mount, and panicking outright on the panic_on_oops builds common in embedded, automotive, and hardened deployments." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/sysctl.c" ], "versions": [ { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "cf387cdebfaebae228dfba162f94c567a67610c3", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "dc583e7e5f8515ca489c0df28e4362a70eade382", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "bd2a2939423566c654545fa3e96a656662a0af9e", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "1b67030d39f2b00f94ac1f0af11ba6657589e4d3", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "7ec30c54f339c640aa7e49d7e9f7bbed6bd42bf6", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "c184bc621e3cef03ac9ba81a50dda2dae6a21d36", "status": "affected", "versionType": "git" }, { "version": "b14878ccb7fac0242db82720b784ab62c467c0dc", "lessThan": "15649fd5415eda664ef35780c2013adeb5d9c695", "status": "affected", "versionType": "git" }, { "version": "e5eae4a0511241959498b180fa0df0d4f1b11b9c", "status": "affected", "versionType": "git" }, { "version": "88830f227a1f96e44d82ddfcb0cc81d517ec6dd8", "status": "affected", "versionType": "git" }, { "version": "3938b0336a93fa5faa242dc9e5823ac69df9e066", "status": "affected", "versionType": "git" }, { "version": "3.10.41", "lessThan": "3.11", "status": "affected", "versionType": "semver" }, { "version": "3.12.21", "lessThan": "3.13", "status": "affected", "versionType": "semver" }, { "version": "3.14.5", "lessThan": "3.15", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sctp/sysctl.c" ], "versions": [ { "version": "3.15", "status": "affected" }, { "version": "0", "lessThan": "3.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.292", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.234", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.177", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.125", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.72", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.10", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13", "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": "3.15", "versionEndExcluding": "5.4.292" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "5.10.234" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "5.15.177" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.1.125" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.6.72" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.12.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10.41" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/cf387cdebfaebae228dfba162f94c567a67610c3" }, { "url": "https://git.kernel.org/stable/c/dc583e7e5f8515ca489c0df28e4362a70eade382" }, { "url": "https://git.kernel.org/stable/c/bd2a2939423566c654545fa3e96a656662a0af9e" }, { "url": "https://git.kernel.org/stable/c/1b67030d39f2b00f94ac1f0af11ba6657589e4d3" }, { "url": "https://git.kernel.org/stable/c/7ec30c54f339c640aa7e49d7e9f7bbed6bd42bf6" }, { "url": "https://git.kernel.org/stable/c/c184bc621e3cef03ac9ba81a50dda2dae6a21d36" }, { "url": "https://git.kernel.org/stable/c/15649fd5415eda664ef35780c2013adeb5d9c695" } ], "title": "sctp: sysctl: auth_enable: avoid using current->nsproxy", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:58:17.877Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:02:58.938Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" } ] } ] } }