{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53751", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-08T01:18:04.279Z", "datePublished": "2025-12-08T01:19:11.160Z", "dateUpdated": "2026-08-05T09:15:47.928Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:15:47.928Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix potential use-after-free bugs in TCP_Server_Info::hostname\n\nTCP_Server_Info::hostname may be updated once or many times during\nreconnect, so protect its access outside reconnect path as well and\nthen prevent any potential use-after-free bugs." } ], "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 vulnerability is in the CIFS/SMB client's handling of remote server data — the freed/reallocated `hostname` is derived from server-supplied DFS referral targets, and both the free side (forced reconnects) and the read side (error-path `cifs_server_dbg(VFS,...)` on malformed or bad-signature responses) are driven entirely by a remote SMB peer or an on-path network attacker.\nAC:L - The attacker controls both sides of the race: it can force unlimited reconnect cycles by dropping the TCP connection, chooses DFS target names so it controls the size and content of the freed/reallocated string for heap grooming, and can trigger the unlocked readers on demand via malformed responses, with unlimited retries.\nPR:N - No credentials or privileges on the target are required — the attacker is the remote SMB server or a network attacker, and the reader side is additionally reachable by any unprivileged local user through the world-readable (0444) /proc/fs/cifs/DebugData and 0644 /proc/fs/cifs/Stats.\nUI:N - Against a host with an already-established DFS CIFS mount (routine on enterprise servers and appliances), the attacker triggers reconnects and error paths on its own; no action by any user is needed at attack time.\nS:U - The use-after-free is in kernel memory and its impact stays within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `seq_printf(\"%s\", server->hostname)` on the dangling pointer copies freed heap memory into the world-readable /proc/fs/cifs/DebugData output, reading until an arbitrary NUL byte, giving an unbounded kernel heap disclosure whose contents the attacker can groom; the same data also leaks to dmesg via `cifs_server_dbg`.\nI:H - This is a use-after-free on an attacker-size-controlled slab object with a racing free/reassign of the same pointer, which enables heap spraying and reclaim of the freed slot; per kernel UAF scoring this is treated as exploitable for control-flow/memory corruption.\nA:H - Dereferencing the freed string over poisoned, unmapped, or reallocated memory produces a kernel oops/panic, and the attacker can repeat the reconnect-driven race indefinitely." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/cifs/cifs_debug.c", "fs/cifs/cifs_debug.h", "fs/cifs/connect.c", "fs/cifs/sess.c" ], "versions": [ { "version": "93d5cb517db39e8af8d1292f9e785e4983b7f708", "lessThan": "64d62ac6d6514cba1305bd08e271ec1843bdd612", "status": "affected", "versionType": "git" }, { "version": "93d5cb517db39e8af8d1292f9e785e4983b7f708", "lessThan": "c511954bf142fe1995aec3c739a9f1a76990283a", "status": "affected", "versionType": "git" }, { "version": "93d5cb517db39e8af8d1292f9e785e4983b7f708", "lessThan": "0b08c4c499200be67d54c439d56e5ea866869945", "status": "affected", "versionType": "git" }, { "version": "93d5cb517db39e8af8d1292f9e785e4983b7f708", "lessThan": "90c49fce1c43e1cc152695e20363ff5087897c09", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/cifs/cifs_debug.c", "fs/cifs/cifs_debug.h", "fs/cifs/connect.c", "fs/cifs/sess.c" ], "versions": [ { "version": "5.0", "status": "affected" }, { "version": "0", "lessThan": "5.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.28", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2.15", "lessThanOrEqual": "6.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.3.2", "lessThanOrEqual": "6.3.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4", "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": "5.0", "versionEndExcluding": "6.1.28" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.2.15" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.3.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0", "versionEndExcluding": "6.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/64d62ac6d6514cba1305bd08e271ec1843bdd612" }, { "url": "https://git.kernel.org/stable/c/c511954bf142fe1995aec3c739a9f1a76990283a" }, { "url": "https://git.kernel.org/stable/c/0b08c4c499200be67d54c439d56e5ea866869945" }, { "url": "https://git.kernel.org/stable/c/90c49fce1c43e1cc152695e20363ff5087897c09" } ], "title": "cifs: fix potential use-after-free bugs in TCP_Server_Info::hostname", "x_generator": { "engine": "bippy-1.2.0" } } } }