{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53597", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-04T15:40:38.479Z", "datePublished": "2025-10-04T15:44:09.616Z", "dateUpdated": "2026-08-05T09:15:00.757Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:15:00.757Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix mid leak during reconnection after timeout threshold\n\nWhen the number of responses with status of STATUS_IO_TIMEOUT\nexceeds a specified threshold (NUM_STATUS_IO_TIMEOUT), we reconnect\nthe connection. But we do not return the mid, or the credits\nreturned for the mid, or reduce the number of in-flight requests.\n\nThis bug could result in the server->in_flight count to go bad,\nand also cause a leak in the mids.\n\nThis change moves the check to a few lines below where the\nresponse is decrypted, even of the response is read from the\ntransform header. This way, the code for returning the mids\ncan be reused.\n\nAlso, the cifs_reconnect was reconnecting just the transport\nconnection before. In case of multi-channel, this may not be\nwhat we want to do after several timeouts. Changed that to\nreconnect the session and the tree too.\n\nAlso renamed NUM_STATUS_IO_TIMEOUT to a more appropriate name\nMAX_STATUS_IO_TIMEOUT." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable code is the CIFS/SMB client demultiplex thread parsing responses received from a remote SMB server over TCP; a malicious, compromised, or MITM-positioned server triggers it purely by the status field it puts in its replies. No local access to the victim is needed.\nAC:L - The server simply returns STATUS_IO_TIMEOUT to six consecutive requests, which deterministically drives the `num_io_timeout > NUM_STATUS_IO_TIMEOUT` path; there is no race, no memory-layout dependency, and no condition outside the attacker's control.\nPR:N - The attacker is the remote peer (or an on-path attacker on an unsigned connection) and holds no privileges whatsoever on the victim client system. Response status codes are attacker-chosen with no authorization gate on the client side.\nUI:N - Exploitation happens on an already-established mount by replying to requests the client issues on its own (writeback, echo, reads), and the client auto-reconnects after each reconnect cycle, so no victim action is required at exploit time.\nS:U - The leaked mids, credits, and stalled I/O are all confined to the kernel of the client host running the cifs module; no security boundary such as a VM or IOMMU domain is crossed.\nC:N - This is a reference/resource leak — an object is over-referenced and never freed. There is no out-of-bounds read, use-after-free, or uninitialized data path, so no information is disclosed to the attacker.\nI:N - No memory is corrupted and no attacker-controlled write occurs; stalled writes leave pages permanently under writeback rather than silently reporting success, so no data is modified or falsified.\nA:H - The bug is repeatable without limit, producing an unbounded kernel memory leak plus permanent `server->in_flight` inflation and credit loss that makes `wait_for_free_credits()` block indefinitely, and skipped read/write callbacks leave pages locked or under writeback forever — yielding unkillable D-state tasks, a hung/unmountable filesystem, and eventual OOM." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/client/connect.c" ], "versions": [ { "version": "8e670f77c4a55013db6d23b962f9bf6673a5e7b6", "lessThan": "df31d05f0678cdd0796ea19983a2b93edca18bb0", "status": "affected", "versionType": "git" }, { "version": "8e670f77c4a55013db6d23b962f9bf6673a5e7b6", "lessThan": "c55901d381a22300c9922170e59704059f50977b", "status": "affected", "versionType": "git" }, { "version": "8e670f77c4a55013db6d23b962f9bf6673a5e7b6", "lessThan": "57d25e9905c71133e201f6d06b56a3403d4ad433", "status": "affected", "versionType": "git" }, { "version": "8e670f77c4a55013db6d23b962f9bf6673a5e7b6", "lessThan": "69cba9d3c1284e0838ae408830a02c4a063104bc", "status": "affected", "versionType": "git" }, { "version": "fa6d7a5853f93efb088aba36af12cb1944156411", "status": "affected", "versionType": "git" }, { "version": "5.9.5", "lessThan": "5.10", "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/connect.c" ], "versions": [ { "version": "5.10", "status": "affected" }, { "version": "0", "lessThan": "5.10", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.150", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.42", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4.7", "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": "5.10", "versionEndExcluding": "5.15.150" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.1.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.4.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/df31d05f0678cdd0796ea19983a2b93edca18bb0" }, { "url": "https://git.kernel.org/stable/c/c55901d381a22300c9922170e59704059f50977b" }, { "url": "https://git.kernel.org/stable/c/57d25e9905c71133e201f6d06b56a3403d4ad433" }, { "url": "https://git.kernel.org/stable/c/69cba9d3c1284e0838ae408830a02c4a063104bc" } ], "title": "cifs: fix mid leak during reconnection after timeout threshold", "x_generator": { "engine": "bippy-1.2.0" } } } }