{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21719", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.753Z", "datePublished": "2025-02-27T02:07:28.573Z", "dateUpdated": "2026-08-05T11:53:54.833Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:53:54.833Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmr: do not call mr_mfc_uses_dev() for unres entries\n\nsyzbot found that calling mr_mfc_uses_dev() for unres entries\nwould crash [1], because c->mfc_un.res.minvif / c->mfc_un.res.maxvif\nalias to \"struct sk_buff_head unresolved\", which contain two pointers.\n\nThis code never worked, lets remove it.\n\n[1]\nUnable to handle kernel paging request at virtual address ffff5fff2d536613\nKASAN: maybe wild-memory-access in range [0xfffefff96a9b3098-0xfffefff96a9b309f]\nModules linked in:\nCPU: 1 UID: 0 PID: 7321 Comm: syz.0.16 Not tainted 6.13.0-rc7-syzkaller-g1950a0af2d55 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\npstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n pc : mr_mfc_uses_dev net/ipv4/ipmr_base.c:290 [inline]\n pc : mr_table_dump+0x5a4/0x8b0 net/ipv4/ipmr_base.c:334\n lr : mr_mfc_uses_dev net/ipv4/ipmr_base.c:289 [inline]\n lr : mr_table_dump+0x694/0x8b0 net/ipv4/ipmr_base.c:334\nCall trace:\n mr_mfc_uses_dev net/ipv4/ipmr_base.c:290 [inline] (P)\n mr_table_dump+0x5a4/0x8b0 net/ipv4/ipmr_base.c:334 (P)\n mr_rtm_dumproute+0x254/0x454 net/ipv4/ipmr_base.c:382\n ipmr_rtm_dumproute+0x248/0x4b4 net/ipv4/ipmr.c:2648\n rtnl_dump_all+0x2e4/0x4e8 net/core/rtnetlink.c:4327\n rtnl_dumpit+0x98/0x1d0 net/core/rtnetlink.c:6791\n netlink_dump+0x4f0/0xbc0 net/netlink/af_netlink.c:2317\n netlink_recvmsg+0x56c/0xe64 net/netlink/af_netlink.c:1973\n sock_recvmsg_nosec net/socket.c:1033 [inline]\n sock_recvmsg net/socket.c:1055 [inline]\n sock_read_iter+0x2d8/0x40c net/socket.c:1125\n new_sync_read fs/read_write.c:484 [inline]\n vfs_read+0x740/0x970 fs/read_write.c:565\n ksys_read+0x15c/0x26c fs/read_write.c:708" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable loop is reached only through an RTM_GETROUTE netlink dump (`rtnl_dump_all` → `ipmr_rtm_dumproute` → `mr_table_dump`) issued on a local AF_NETLINK socket. Although the unresolved cache entry itself is created by an incoming multicast packet, the crash requires the local netlink request, so the attack vector is Local.\nAC:L - The attacker fully controls both halves — creating unresolved MFC entries by sending multicast packets into a vif, and issuing the RTA_OIF-filtered strict-check dump — and can repeat this arbitrarily until an entry whose aliased pointer halves satisfy `minvif < maxvif` is walked. No condition outside the attacker's influence is required.\nPR:L - Netlink route dumps require no capability at all (rtnetlink only enforces CAP_NET_ADMIN for non-GET messages), and the multicast-routing setup that populates `mfc_unres_queue` is gated on CAP_NET_RAW/`ns_capable(net->user_ns, CAP_NET_ADMIN)`, both obtainable by any unprivileged user via `unshare -Urn`. On a host already running a multicast routing daemon, an unprivileged user needs only the dump.\nUI:N - The attacker performs every step itself — socket setup, multicast packet injection, and the netlink dump — with no action by any other user or administrator.\nS:U - The out-of-bounds access and its consequences are confined to the kernel's own memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The loop performs unbounded, wild out-of-bounds reads of kernel memory at indices derived from a heap pointer, spanning arbitrarily far outside `mrt->vif_table` and the mfc allocation, and the result feeds a userspace-observable dump-filtering decision that acts as an oracle on that out-of-bounds kernel memory.\nI:N - `mr_mfc_uses_dev()` is a purely read-only loop and `mr_fill_mroute()` returns early for unresolved entries, so no kernel memory is written or corrupted by this bug.\nA:H - The wild indexing causes a kernel paging fault / KASAN wild-memory-access oops, as reported by syzbot, and the near-billion-iteration loop runs while holding `mfc_unres_lock` with softirqs disabled, risking soft lockup and RCU stalls — a reliably reproducible kernel crash or hang." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/ipmr_base.c" ], "versions": [ { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "71a0fcb68c0a5f3ec912b540cd5d72148e6ee5f1", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "53df27fd38f84bd3cd6b004eb4ff3c4903114f1d", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "547ef7e8cbb98f966c8719a3e15d4e078aaa9b47", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "57177c5f47a8da852f8d76cf6945cf803f8bb9e5", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "b379b3162ff55a70464c6a934ae9bf0497478a62", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "a099834a51ccf9bbba3de86a251b3433539abfde", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "26bb7d991f04eeef47dfad23e533834995c26f7a", "status": "affected", "versionType": "git" }, { "version": "cb167893f41e21e6bd283d78e53489289dc0592d", "lessThan": "15a901361ec3fb1c393f91880e1cbf24ec0a88bd", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/ipmr_base.c" ], "versions": [ { "version": "4.20", "status": "affected" }, { "version": "0", "lessThan": "4.20", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.291", "lessThanOrEqual": "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": "4.20", "versionEndExcluding": "5.4.291" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.10.235" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.1.129" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.6.76" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.12.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.13.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/71a0fcb68c0a5f3ec912b540cd5d72148e6ee5f1" }, { "url": "https://git.kernel.org/stable/c/53df27fd38f84bd3cd6b004eb4ff3c4903114f1d" }, { "url": "https://git.kernel.org/stable/c/547ef7e8cbb98f966c8719a3e15d4e078aaa9b47" }, { "url": "https://git.kernel.org/stable/c/57177c5f47a8da852f8d76cf6945cf803f8bb9e5" }, { "url": "https://git.kernel.org/stable/c/b379b3162ff55a70464c6a934ae9bf0497478a62" }, { "url": "https://git.kernel.org/stable/c/a099834a51ccf9bbba3de86a251b3433539abfde" }, { "url": "https://git.kernel.org/stable/c/26bb7d991f04eeef47dfad23e533834995c26f7a" }, { "url": "https://git.kernel.org/stable/c/15a901361ec3fb1c393f91880e1cbf24ec0a88bd" } ], "title": "ipmr: do not call mr_mfc_uses_dev() for unres entries", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "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": "2025-11-03T19:36:16.326Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:03:27.250Z" }, "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" } ] } ] } }