{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53794", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-08T23:58:35.274Z", "datePublished": "2025-12-09T00:00:51.061Z", "dateUpdated": "2026-08-05T09:16:01.824Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:16:01.824Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix session state check in reconnect to avoid use-after-free issue\n\nDon't collect exiting session in smb2_reconnect_server(), because it\nwill be released soon.\n\nNote that the exiting session will stay in server->smb_ses_list until\nit complete the cifs_free_ipc() and logoff() and then delete itself\nfrom the list." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable code is the SMB/CIFS client's reconnect worker, whose execution and timing are dictated entirely by a remote SMB peer (TCP resets, malformed PDUs, STATUS_NETWORK_SESSION_EXPIRED, stalled SMB2_LOGOFF replies, DFS referrals). A malicious/compromised file server or an on-path attacker triggers it purely over TCP/445 with no local access.\nAC:L - The attacker controls both sides of the race: it stalls the SMB2_LOGOFF response to hold the session in SES_EXITING on smb_ses_list for the full response timeout, while forcing smb2_reconnect_server() to run on demand and repeatedly (it also self-requeues every 2 seconds), making the window trivially wide and the hit near-certain.\nPR:N - No credentials or privileges on the victim system are required — the attacker is the remote server (or an on-path attacker) acting against an existing mount, and the triggering conditions are protocol-level responses that require no authenticated privilege on the client.\nUI:N - Against an already-established mount (fstab, autofs, systemd automount, container share) the attack proceeds with no victim action; the session teardown side is generated by normal client activity such as DFS referral handling and session churn that the attacker itself induces.\nS:U - The freed and reused objects (struct cifs_ses, struct cifs_tcon) and the resulting corruption all live within the kernel's own security authority, with no crossing into a hypervisor, IOMMU, or other security scope.\nC:H - A use-after-free on a heap-allocated cifs_ses/cifs_tcon lets the attacker groom the freed slab and have the reconnect path read session fields (Suid, auth_key.response, chans[], dfs_root_ses) out of attacker-influenced memory, yielding a kernel information-disclosure primitive.\nI:H - The worker writes into the freed objects — list_add_tail() stores two pointers into ses->rlist and the freed tcon_ipc->rlist, ses_count is incremented through a dangling dfs_root_ses pointer, and cifs_setup_session() writes ses_status/Suid and frees ses->auth_key.response — giving write and controlled-free primitives usable for control-flow hijack.\nA:H - The use-after-free reliably corrupts kernel memory, taking spinlocks and mutexes inside a freed allocation and corrupting list heads, which oopses or panics the machine and can hang the cifs workqueue." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/smb2pdu.c" ], "versions": [ { "version": "4fcd1813e6404dd4420c7d12fb483f9320f0bf93", "lessThan": "7e4f5c3f01fb0e51ca438e43262d858daf9a0a76", "status": "affected", "versionType": "git" }, { "version": "4fcd1813e6404dd4420c7d12fb483f9320f0bf93", "lessThan": "759ffc164d95a32c09528766d74d9b4fb054e8f4", "status": "affected", "versionType": "git" }, { "version": "4fcd1813e6404dd4420c7d12fb483f9320f0bf93", "lessThan": "99f280700b4cc02d5f141b8d15f8e9fad0418f65", "status": "affected", "versionType": "git" }, { "version": "655e0c067f0e02ece03fd0591dabe3db2ae27552", "status": "affected", "versionType": "git" }, { "version": "875cc09c0767a4ac06b57af383709657f98b3ea1", "status": "affected", "versionType": "git" }, { "version": "599fe1409085059ba12a2c3897c853be9fa9e7cf", "status": "affected", "versionType": "git" }, { "version": "2e4378ee60049b752c9dce16f62ce6fbd11b379a", "status": "affected", "versionType": "git" }, { "version": "59b520454b323ec43b2ae757217332cea33091e0", "status": "affected", "versionType": "git" }, { "version": "e20c888e2b3576e5f498c167729d274ef60b86f8", "status": "affected", "versionType": "git" }, { "version": "4ce7aa4e44d88ce64ea8ae2337b8910f3670b0ba", "status": "affected", "versionType": "git" }, { "version": "419fad68e4c4135ff9859e9214dd6cf954413ca1", "status": "affected", "versionType": "git" }, { "version": "3.10.103", "lessThan": "3.11", "status": "affected", "versionType": "semver" }, { "version": "3.12.63", "lessThan": "3.13", "status": "affected", "versionType": "semver" }, { "version": "3.14.74", "lessThan": "3.15", "status": "affected", "versionType": "semver" }, { "version": "3.16.37", "lessThan": "3.17", "status": "affected", "versionType": "semver" }, { "version": "3.18.37", "lessThan": "3.19", "status": "affected", "versionType": "semver" }, { "version": "4.1.28", "lessThan": "4.2", "status": "affected", "versionType": "semver" }, { "version": "4.4.16", "lessThan": "4.5", "status": "affected", "versionType": "semver" }, { "version": "4.6.5", "lessThan": "4.7", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/smb2pdu.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.47", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4.12", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.5", "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": "4.7", "versionEndExcluding": "6.1.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.4.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12.63" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.14.74" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.16.37" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.18.37" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1.28" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7e4f5c3f01fb0e51ca438e43262d858daf9a0a76" }, { "url": "https://git.kernel.org/stable/c/759ffc164d95a32c09528766d74d9b4fb054e8f4" }, { "url": "https://git.kernel.org/stable/c/99f280700b4cc02d5f141b8d15f8e9fad0418f65" } ], "title": "cifs: fix session state check in reconnect to avoid use-after-free issue", "x_generator": { "engine": "bippy-1.2.0" } } } }