{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40253", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.181Z", "datePublished": "2025-12-04T16:08:15.340Z", "dateUpdated": "2026-08-05T12:08:55.944Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:55.944Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/ctcm: Fix double-kfree\n\nThe function 'mpc_rcvd_sweep_req(mpcginfo)' is called conditionally\nfrom function 'ctcmpc_unpack_skb'. It frees passed mpcginfo.\nAfter that a call to function 'kfree' in function 'ctcmpc_unpack_skb'\nfrees it again.\n\nRemove 'kfree' call in function 'mpc_rcvd_sweep_req(mpcginfo)'.\n\nBug detected by the clang static analyzer." } ], "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 malicious `TH_SWEEP_REQ` transmission header is delivered as a link-level MPC frame by the directly-attached CTC peer (a partner LPAR or a z/VM guest coupled via virtual CTCA), reaching `ctcmpc_unpack_skb()` straight from the channel read interrupt. MPC TH headers are regenerated per link and not routable, so the attacker must sit on the adjacent channel connection rather than across a routed network.\nAC:L - A single frame with `th_ch_flag = 0xfe` deterministically drives `ctcmpc_unpack_skb()` into `mpc_rcvd_sweep_req()` and the two consecutive `kfree()` calls every time — no race, no timing window, and no memory-layout precondition outside the attacker's control.\nPR:N - The attacker needs no account, credential, or capability on the target Linux image; it only has to be the CTC peer, and the path is reachable both in `MPCG_STATE_READY` and during the pre-establishment XID-negotiation states, where no authentication of any kind has occurred.\nUI:N - The remote peer triggers the double free entirely on its own by transmitting one frame on an already-active CTC link; no administrator or user action on the victim system is needed at attack time.\nS:U - The slab corruption occurs in the receiving kernel's own softirq/tasklet context and its consequences stay within that kernel's security authority; no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - On kernels without freelist hardening the double free leaves the kmalloc-64 percpu freelist self-referential, so repeated allocations hand the same 40-byte object to unrelated kernel structures, yielding an aliasing/use-after-free primitive that exposes arbitrary kernel memory contents to the attacker-controlled objects.\nI:H - The same freelist corruption lets attacker-influenced allocations overlap live kernel objects (type confusion), giving a write primitive over adjacent/aliased kernel data and a realistic path to control-flow hijack — classic exploitable heap corruption, not a mere accounting error.\nA:H - With `CONFIG_SLAB_FREELIST_HARDENED` the immediate double free hits `BUG_ON(object == fp)` in `set_freepointer()` inside a tasklet, which is fatal in interrupt context; without it the corrupted freelist causes near-certain crashes, and either outcome is re-triggerable at will by the peer." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/net/ctcm_mpc.c" ], "versions": [ { "version": "467ddbbe7e749d558f13e640f50f546149c930b3", "lessThan": "06f1dd1de0d33dbfbd2e1fc9fc57d8895f730de2", "status": "affected", "versionType": "git" }, { "version": "4d3c6d741816539b57fa1110c3f765a8c176d7b4", "lessThan": "6bf8ccaabce8cebb6cb1f255c93d0acdfe95c17a", "status": "affected", "versionType": "git" }, { "version": "2bd57101c3ecf3f8c0da1d26c2b6ad511adc6d50", "lessThan": "7616e2eee679746d526c7f5befd4eedb995935b5", "status": "affected", "versionType": "git" }, { "version": "0c0b20587b9f25a2ad14db7f80ebe49bdf29920a", "lessThan": "43096dab8cc60fc39133205fd149a54d3acebea8", "status": "affected", "versionType": "git" }, { "version": "0c0b20587b9f25a2ad14db7f80ebe49bdf29920a", "lessThan": "3b177b2ded563df16f6d5920671ffcfe5915d472", "status": "affected", "versionType": "git" }, { "version": "0c0b20587b9f25a2ad14db7f80ebe49bdf29920a", "lessThan": "b9dbfb1b5699f9f1e4991f96741bdf9047147589", "status": "affected", "versionType": "git" }, { "version": "0c0b20587b9f25a2ad14db7f80ebe49bdf29920a", "lessThan": "7ff76f8dc6b550f8d16487bf3cebc278be720b5c", "status": "affected", "versionType": "git" }, { "version": "0c0b20587b9f25a2ad14db7f80ebe49bdf29920a", "lessThan": "da02a1824884d6c84c5e5b5ac373b0c9e3288ec2", "status": "affected", "versionType": "git" }, { "version": "36933de59f67029e5739a98393891f9b94f27e0f", "status": "affected", "versionType": "git" }, { "version": "d886b4292a1c5b4facdb2dfdc31f0fecc71df898", "status": "affected", "versionType": "git" }, { "version": "4c9ba0fed125deba8416b995b0c274b0804c0c24", "status": "affected", "versionType": "git" }, { "version": "ea0053af5dab4d63a9c44563973fb2f3bfd9eb2b", "status": "affected", "versionType": "git" }, { "version": "5.4.195", "lessThan": "5.4.302", "status": "affected", "versionType": "semver" }, { "version": "5.10.117", "lessThan": "5.10.247", "status": "affected", "versionType": "semver" }, { "version": "5.15.41", "lessThan": "5.15.197", "status": "affected", "versionType": "semver" }, { "version": "4.9.315", "lessThan": "4.10", "status": "affected", "versionType": "semver" }, { "version": "4.14.280", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.244", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.17.9", "lessThan": "5.18", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/net/ctcm_mpc.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.302", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.247", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.197", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.118", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.10", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "5.4.195", "versionEndExcluding": "5.4.302" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.117", "versionEndExcluding": "5.10.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.41", "versionEndExcluding": "5.15.197" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.1.159" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.6.118" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.12.60" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.17.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.315" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.280" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.244" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/06f1dd1de0d33dbfbd2e1fc9fc57d8895f730de2" }, { "url": "https://git.kernel.org/stable/c/6bf8ccaabce8cebb6cb1f255c93d0acdfe95c17a" }, { "url": "https://git.kernel.org/stable/c/7616e2eee679746d526c7f5befd4eedb995935b5" }, { "url": "https://git.kernel.org/stable/c/43096dab8cc60fc39133205fd149a54d3acebea8" }, { "url": "https://git.kernel.org/stable/c/3b177b2ded563df16f6d5920671ffcfe5915d472" }, { "url": "https://git.kernel.org/stable/c/b9dbfb1b5699f9f1e4991f96741bdf9047147589" }, { "url": "https://git.kernel.org/stable/c/7ff76f8dc6b550f8d16487bf3cebc278be720b5c" }, { "url": "https://git.kernel.org/stable/c/da02a1824884d6c84c5e5b5ac373b0c9e3288ec2" } ], "title": "s390/ctcm: Fix double-kfree", "x_generator": { "engine": "bippy-1.2.0" } } } }