{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53072", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-05-02T15:51:43.548Z", "datePublished": "2025-05-02T15:55:23.765Z", "dateUpdated": "2026-08-05T09:12:36.982Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:12:36.982Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: use the workqueue to destroy unaccepted sockets\n\nChristoph reported a UaF at token lookup time after having\nrefactored the passive socket initialization part:\n\n BUG: KASAN: use-after-free in __token_bucket_busy+0x253/0x260\n Read of size 4 at addr ffff88810698d5b0 by task syz-executor653/3198\n\n CPU: 1 PID: 3198 Comm: syz-executor653 Not tainted 6.2.0-rc59af4eaa31c1f6c00c8f1e448ed99a45c66340dd5 #6\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n Call Trace:\n \n dump_stack_lvl+0x6e/0x91\n print_report+0x16a/0x46f\n kasan_report+0xad/0x130\n __token_bucket_busy+0x253/0x260\n mptcp_token_new_connect+0x13d/0x490\n mptcp_connect+0x4ed/0x860\n __inet_stream_connect+0x80e/0xd90\n tcp_sendmsg_fastopen+0x3ce/0x710\n mptcp_sendmsg+0xff1/0x1a20\n inet_sendmsg+0x11d/0x140\n __sys_sendto+0x405/0x490\n __x64_sys_sendto+0xdc/0x1b0\n do_syscall_64+0x3b/0x90\n entry_SYSCALL_64_after_hwframe+0x72/0xdc\n\nWe need to properly clean-up all the paired MPTCP-level\nresources and be sure to release the msk last, even when\nthe unaccepted subflow is destroyed by the TCP internals\nvia inet_child_forget().\n\nWe can re-use the existing MPTCP_WORK_CLOSE_SUBFLOW infra,\nexplicitly checking that for the critical scenario: the\nclosed subflow is the MPC one, the msk is not accepted and\neventually going through full cleanup.\n\nWith such change, __mptcp_destroy_sock() is always called\non msk sockets, even on accepted ones. We don't need anymore\nto transiently drop one sk reference at msk clone time.\n\nPlease note this commit depends on the parent one:\n\n mptcp: refactor passive socket initialization" } ], "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 reliable trigger is an unprivileged local process creating an IPPROTO_MPTCP listener and connecting to it (syzkaller socket/bind/listen/sendto TFO reproducer); inet_child_forget() only frees the unaccepted msk when the listener is not in TCP_LISTEN, which the attacker drives via their own sockets rather than unsolicited remote packets alone.\nAC:L - The attacker fully controls both the listener and the connecting peer and can force inet_child_forget() to drop the sole msk reference without mptcp_token_destroy(), leaving the freed sock in the token hash; syzkaller reproduced this reliably with no dependency on external timing or layout.\nPR:L - Creating, binding, and listening on IPPROTO_MPTCP sockets needs only an unprivileged local account (net.mptcp.enabled defaults to 1; mptcp_init_sock has no CAP_* gate), including inside user/net namespaces.\nUI:N - Exploitation uses only the attacker's own MPTCP sockets and connect/close syscalls; no separate victim action is required.\nS:U - This is a same-host kernel slab UAF/privilege-escalation class bug; impact stays within the kernel's security authority with no VM, IOMMU, or sandbox boundary crossed.\nC:H - The UAF leaves a freed kmalloc-2k mptcp/struct sock linked in the global token hash, so later __token_lookup_msk/mptcp_token_get_sock walks attacker-reclaimable memory and can disclose arbitrary kernel data.\nI:H - Reclaiming the freed sock in the token hash enables fake-object injection and subsequent MPTCP paths (including refcount updates via mptcp_token_get_sock) to act on attacker-controlled memory for arbitrary write and control-flow hijack.\nA:H - The UAF already produces a KASAN use-after-free oops in __token_bucket_busy and can soft-lockup in mptcp_token_exists on a corrupted hash chain, crashing or hanging the kernel even without further exploitation." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mptcp/protocol.c", "net/mptcp/protocol.h", "net/mptcp/subflow.c" ], "versions": [ { "version": "58b09919626bf9067345289212ec030c61eb1034", "lessThan": "2827f099b3fb9a59263c997400e9182f5d423e84", "status": "affected", "versionType": "git" }, { "version": "58b09919626bf9067345289212ec030c61eb1034", "lessThan": "804cf487fb0031f3c74755b78d8663333f0ba636", "status": "affected", "versionType": "git" }, { "version": "58b09919626bf9067345289212ec030c61eb1034", "lessThan": "b6985b9b82954caa53f862d6059d06c0526254f0", "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/mptcp/protocol.c", "net/mptcp/protocol.h", "net/mptcp/subflow.c" ], "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.22", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2.8", "lessThanOrEqual": "6.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.3", "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": "5.7", "versionEndExcluding": "6.1.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2827f099b3fb9a59263c997400e9182f5d423e84" }, { "url": "https://git.kernel.org/stable/c/804cf487fb0031f3c74755b78d8663333f0ba636" }, { "url": "https://git.kernel.org/stable/c/b6985b9b82954caa53f862d6059d06c0526254f0" } ], "title": "mptcp: use the workqueue to destroy unaccepted sockets", "x_generator": { "engine": "bippy-1.2.0" } } } }