{ "dataType": "CVE_RECORD", "cveMetadata": { "cveId": "CVE-2024-26960", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.201Z", "datePublished": "2024-05-01T05:19:12.112Z", "dateUpdated": "2026-08-05T11:28:38.708Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:28:38.708Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: swap: fix race between free_swap_and_cache() and swapoff()\n\nThere was previously a theoretical window where swapoff() could run and\nteardown a swap_info_struct while a call to free_swap_and_cache() was\nrunning in another thread. This could cause, amongst other bad\npossibilities, swap_page_trans_huge_swapped() (called by\nfree_swap_and_cache()) to access the freed memory for swap_map.\n\nThis is a theoretical problem and I haven't been able to provoke it from a\ntest case. But there has been agreement based on code review that this is\npossible (see link below).\n\nFix it by using get_swap_device()/put_swap_device(), which will stall\nswapoff(). There was an extra check in _swap_info_get() to confirm that\nthe swap entry was not free. This isn't present in get_swap_device()\nbecause it doesn't make sense in general due to the race between getting\nthe reference and swapoff. So I've added an equivalent check directly in\nfree_swap_and_cache().\n\nDetails of how to provoke one possible issue (thanks to David Hildenbrand\nfor deriving this):\n\n--8<-----\n\n__swap_entry_free() might be the last user and result in\n\"count == SWAP_HAS_CACHE\".\n\nswapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0.\n\nSo the question is: could someone reclaim the folio and turn\nsi->inuse_pages==0, before we completed swap_page_trans_huge_swapped().\n\nImagine the following: 2 MiB folio in the swapcache. Only 2 subpages are\nstill references by swap entries.\n\nProcess 1 still references subpage 0 via swap entry.\nProcess 2 still references subpage 1 via swap entry.\n\nProcess 1 quits. Calls free_swap_and_cache().\n-> count == SWAP_HAS_CACHE\n[then, preempted in the hypervisor etc.]\n\nProcess 2 quits. Calls free_swap_and_cache().\n-> count == SWAP_HAS_CACHE\n\nProcess 2 goes ahead, passes swap_page_trans_huge_swapped(), and calls\n__try_to_reclaim_swap().\n\n__try_to_reclaim_swap()->folio_free_swap()->delete_from_swap_cache()->\nput_swap_folio()->free_swap_slot()->swapcache_free_entries()->\nswap_entry_free()->swap_range_free()->\n...\nWRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries);\n\nWhat stops swapoff to succeed after process 2 reclaimed the swap cache\nbut before process1 finished its call to swap_page_trans_huge_swapped()?\n\n--8<-----" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached only through local memory-management syscalls — `munmap`/`exit` (`zap_pte_range` → mm/memory.c:1636), `madvise(MADV_DONTNEED/MADV_FREE)` (mm/madvise.c:659), and tmpfs truncate/punch-hole (mm/shmem.c:842). No remote or adjacent-network consumer reaches `free_swap_and_cache()`.\nAC:H - The attacker controls only their half of the race; the other half is `swapoff()`, gated by `capable(CAP_SYS_ADMIN)` in the *initial* user namespace (mm/swapfile.c:2411, `capable()` not `ns_capable()`), so it cannot be induced from a user namespace and must be performed by an administrator or system script. Landing the hit additionally requires being preempted inside a sub-microsecond window between `__swap_entry_free()` and `swap_page_trans_huge_swapped()` while a second process reclaims the last swapcache reference — the author explicitly could not provoke it from a test case.\nPR:L - The attacker-controlled side needs nothing beyond an ordinary unprivileged local account: any process can spin `munmap`/`madvise`/tmpfs-punch loops over swapped-out anonymous pages to drive `free_swap_and_cache()` at high rate. No capability, namespace, or filesystem privilege is required for that half.\nUI:N - No victim is tricked into any action; the required `swapoff()` is routine system activity (systemd swap-unit deactivation, hibernate scripts, Android zram reconfiguration) that occurs without human participation, and that environmental dependency is already accounted for in AC:H rather than counted twice as UI:R.\nS:U - The corruption is confined to kernel data structures within the kernel's own security authority — standard local kernel memory corruption / privilege escalation. No VM, hypervisor, or IOMMU boundary is crossed.\nC:H - Use-after-free reads of the vfree'd `swap_map`, the kvfree'd `cluster_info`, and a freed `struct address_space` (XArray walk in `filemap_get_folio()`) can disclose reallocated kernel memory. Additionally, `swapoff`+`swapon` reuses the `swap_info_struct` slot, so the stale `free_swap_and_cache()` corrupts the *new* device's counts and prematurely frees slots still referenced by other processes, handing a victim's swapped-out anonymous data to the attacker on swap-in.\nI:H - `lock_cluster()` performs `spin_lock(&ci->lock)` on the kvfree'd `cluster_info` — for typical swap sizes a kmalloc-slab object — giving a sprayable use-after-free *write* primitive, and `__try_to_reclaim_swap()` manipulates folio locks/refcounts derived from a freed `address_space`. Combined with silent swap-map count corruption after `swapon` reuse, this is exploitable for control-flow hijack and cross-process data modification.\nA:H - The most likely immediate outcome is a kernel oops — dereferencing a NULLed `si->swap_map`, faulting in the unmapped vfree'd vmalloc range, a NULL `swapper_spaces[type]`, or tripping `VM_BUG_ON(count != SWAP_HAS_CACHE)` in `__swap_entry_free_locked()`. Any of these panics the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/swapfile.c" ], "versions": [ { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "d85c11c97ecf92d47a4b29e3faca714dc1f18d0d", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "2da5568ee222ce0541bfe446a07998f92ed1643e", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "1ede7f1d7eed1738d1b9333fd1e152ccb450b86a", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "0f98f6d2fb5fad00f8299b84b85b6bc1b6d7d19a", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "3ce4c4c653e4e478ecb15d3c88e690f12cbf6b39", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "363d17e7f7907c8e27a9e86968af0eaa2301787b", "status": "affected", "versionType": "git" }, { "version": "7c00bafee87c7bac7ed9eced7c161f8e5332cb4e", "lessThan": "82b1c07a0af603e3c47b906c8e991dc96f01688e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/swapfile.c" ], "versions": [ { "version": "4.11", "status": "affected" }, { "version": "0", "lessThan": "4.11", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.215", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.154", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.84", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.24", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.12", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8.3", "lessThanOrEqual": "6.8.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9", "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": "4.11", "versionEndExcluding": "5.10.215" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.15.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.1.84" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.6.24" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.7.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.8.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d85c11c97ecf92d47a4b29e3faca714dc1f18d0d" }, { "url": "https://git.kernel.org/stable/c/2da5568ee222ce0541bfe446a07998f92ed1643e" }, { "url": "https://git.kernel.org/stable/c/1ede7f1d7eed1738d1b9333fd1e152ccb450b86a" }, { "url": "https://git.kernel.org/stable/c/0f98f6d2fb5fad00f8299b84b85b6bc1b6d7d19a" }, { "url": "https://git.kernel.org/stable/c/3ce4c4c653e4e478ecb15d3c88e690f12cbf6b39" }, { "url": "https://git.kernel.org/stable/c/363d17e7f7907c8e27a9e86968af0eaa2301787b" }, { "url": "https://git.kernel.org/stable/c/82b1c07a0af603e3c47b906c8e991dc96f01688e" } ], "title": "mm: swap: fix race between free_swap_and_cache() and swapoff()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "cweId": "CWE-362", "lang": "en", "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')" } ] } ], "affected": [ { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "d85c11c97ecf", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "2da5568ee222", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "1ede7f1d7eed", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "0f98f6d2fb5f", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "3ce4c4c653e4", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "363d17e7f790", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "7c00bafee87c", "status": "affected", "lessThan": "82b1c07a0af6", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "5.10.215", "status": "unaffected", "lessThan": "5.11", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "6.1.84", "status": "unaffected", "lessThan": "6.2", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "6.6.24", "status": "unaffected", "lessThan": "6.7", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "6.8.3", "status": "unaffected", "lessThan": "6.9", "versionType": "custom" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "6.9", "status": "unaffected" } ] }, { "vendor": "linux", "product": "linux_kernel", "cpes": [ "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*" ], "defaultStatus": "unknown", "versions": [ { "version": "0", "status": "unaffected", "lessThan": "4.11", "versionType": "custom" } ] }, { "vendor": "linux", "product": 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"privilegesRequired": "LOW", "confidentialityImpact": "NONE" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2025-02-05T21:09:23.358079Z", "id": "CVE-2024-26960", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-05T21:09:44.704Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T00:21:06.048Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/d85c11c97ecf92d47a4b29e3faca714dc1f18d0d", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/2da5568ee222ce0541bfe446a07998f92ed1643e", "tags": [ "x_transferred" ] }, { "url": 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"version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" } ] } ] }, "dataVersion": "5.2" }