{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21727", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.754Z", "datePublished": "2025-02-27T02:07:33.501Z", "dateUpdated": "2026-08-05T11:54:00.224Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:00.224Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npadata: fix UAF in padata_reorder\n\nA bug was found when run ltp test:\n\nBUG: KASAN: slab-use-after-free in padata_find_next+0x29/0x1a0\nRead of size 4 at addr ffff88bbfe003524 by task kworker/u113:2/3039206\n\nCPU: 0 PID: 3039206 Comm: kworker/u113:2 Kdump: loaded Not tainted 6.6.0+\nWorkqueue: pdecrypt_parallel padata_parallel_worker\nCall Trace:\n\ndump_stack_lvl+0x32/0x50\nprint_address_description.constprop.0+0x6b/0x3d0\nprint_report+0xdd/0x2c0\nkasan_report+0xa5/0xd0\npadata_find_next+0x29/0x1a0\npadata_reorder+0x131/0x220\npadata_parallel_worker+0x3d/0xc0\nprocess_one_work+0x2ec/0x5a0\n\nIf 'mdelay(10)' is added before calling 'padata_find_next' in the\n'padata_reorder' function, this issue could be reproduced easily with\nltp test (pcrypt_aead01).\n\nThis can be explained as bellow:\n\npcrypt_aead_encrypt\n...\npadata_do_parallel\nrefcount_inc(&pd->refcnt); // add refcnt\n...\npadata_do_serial\npadata_reorder // pd\nwhile (1) {\npadata_find_next(pd, true); // using pd\nqueue_work_on\n...\npadata_serial_worker\t\t\t\tcrypto_del_alg\npadata_put_pd_cnt // sub refcnt\n\t\t\t\t\t\tpadata_free_shell\n\t\t\t\t\t\tpadata_put_pd(ps->pd);\n\t\t\t\t\t\t// pd is freed\n// loop again, but pd is freed\n// call padata_find_next, UAF\n}\n\nIn the padata_reorder function, when it loops in 'while', if the alg is\ndeleted, the refcnt may be decreased to 0 before entering\n'padata_find_next', which leads to UAF.\n\nAs mentioned in [1], do_serial is supposed to be called with BHs disabled\nand always happen under RCU protection, to address this issue, add\nsynchronize_rcu() in 'padata_free_shell' wait for all _do_serial calls\nto finish.\n\n[1] https://lore.kernel.org/all/20221028160401.cccypv4euxikusiq@parnassus.localdomain/\n[2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/" } ], "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 vulnerable padata/pcrypt path is driven through local syscalls — an AF_ALG socket bound to `pcrypt(...)` submitting aead requests, and the racing teardown via crypto module autoload or the NETLINK_CRYPTO socket. No remote peer can reach or free the padata shell on its own.\nAC:L - The attacker controls both sides of the race: they flood concurrent pcrypt requests to keep `padata_reorder()` spinning in its loop while triggering instance teardown, and can widen the window with CPU contention and many parallel workers. The commit confirms it reproduces with a stock LTP test (pcrypt_aead01) once the loop is delayed, meaning it is a naturally occurring, repeatable window.\nPR:L - A basic unprivileged local user can both instantiate and continuously drive pcrypt via AF_ALG (`alg_bind` performs no capability check) and trigger the teardown side, since `crypto_alg_finish_registration()` → `crypto_remove_spawns()` destroys the pcrypt instance when an equal-or-higher-priority same-named implementation registers — a module autoload reachable from the same unprivileged bind path.\nUI:N - Exploitation is entirely attacker-driven through socket operations and crypto requests; no victim action, mount, or file open is required.\nS:U - The use-after-free corrupts kernel slab memory and stays within the kernel's own security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - Reclaiming the freed `struct parallel_data` gives the attacker control of `pd->reorder_list`, whose per-CPU dereference in `padata_find_next()` becomes an attacker-directed kernel read, and `pd->ps->pinst` is likewise dereferenced — yielding disclosure of arbitrary kernel memory.\nI:H - The same UAF provides write primitives — `list_del_init()` unlink on an attacker-controlled reorder list, `++pd->processed` / `pd->cpu` writes, and most severely `queue_work(pinst->serial_wq, &pd->reorder_work)` invoking a function pointer living in freed, sprayable memory, enabling control-flow hijack and privilege escalation.\nA:H - Even unweaponized, the slab-use-after-free reported by KASAN dereferences freed percpu and workqueue pointers from a kworker context, reliably producing an oops or kernel panic and taking the system down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/padata.c" ], "versions": [ { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "f78170bee51469734b1a306a74fc5f777bb22ba6", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "f3e0b9f790f8e8065d59e67b565a83154d9f3079", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "573ac9c70bf7885dc85d82fa44550581bfc3b738", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "80231f069240d52e98b6a317456c67b2eafd0781", "status": "affected", "versionType": "git" }, { "version": "b128a30409356df65f1a51cff3eb986cac8cfedc", "lessThan": "e01780ea4661172734118d2a5f41bc9720765668", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/padata.c" ], "versions": [ { "version": "5.4", "status": "affected" }, { "version": "0", "lessThan": "5.4", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.235", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.179", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.129", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.76", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.13", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.2", "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": "5.4", "versionEndExcluding": "5.10.235" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "6.1.129" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "6.6.76" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "6.12.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "6.13.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f78170bee51469734b1a306a74fc5f777bb22ba6" }, { "url": "https://git.kernel.org/stable/c/f3e0b9f790f8e8065d59e67b565a83154d9f3079" }, { "url": "https://git.kernel.org/stable/c/0ae2f332cfd2d74cf3ce344ec9938cf3e29c3ccd" }, { "url": "https://git.kernel.org/stable/c/bbccae982e9fa1d7abcb23a5ec81cb0ec883f7de" }, { "url": "https://git.kernel.org/stable/c/573ac9c70bf7885dc85d82fa44550581bfc3b738" }, { "url": "https://git.kernel.org/stable/c/80231f069240d52e98b6a317456c67b2eafd0781" }, { "url": "https://git.kernel.org/stable/c/e01780ea4661172734118d2a5f41bc9720765668" } ], "title": "padata: fix UAF in padata_reorder", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ 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"references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:36:30.604Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:03:30.794Z" }, "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" } ] } ] } }