{ "schema_version": "1.6.1", "id": "RPI-CVE-2024-35864", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2024-35864" ], "published": "2024-05-19T08:35:32Z", "summary": "smb: client: fix potential UAF in smb2_is_valid_lease_break()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix potential UAF in smb2_is_valid_lease_break()\n\nSkip sessions that are being teared down (status == SES_EXITING) to\navoid UAF.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt2", "1:6.1.47-1+rpt4", "1:6.1.54-1+rpt2", "1:6.1.58-1+rpt2", "1:6.1.63-1+rpt1", "1:6.1.73-1+rpt1", "1:6.6.20-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi2-rpi-v6", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v7", "binary_version": 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"655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.85" }, "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.85", "compiled_filter": false }, "1:6.1.54-1+rpt2": { "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7", "upstream_version": "6.1.54", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.85" }, "1:6.1.58-1+rpt2": { "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18", "upstream_version": "6.1.58", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.85" }, "1:6.1.63-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.63", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.85" }, "1:6.1.73-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.73", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.85" }, "1:6.6.20-1+rpt1": { "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668", "upstream_version": "6.6.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.26" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2024-35864" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c868cabdf6fdd61bea54532271f4708254e57fc5" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f92739fdd4522c4291277136399353d7c341fae4" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/a8344e2b69bde63f713b0aa796d70dbeadffddfb" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/705c76fbf726c7a2f6ff9143d4013b18daaaebf1" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T11:52:36Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 9.8, "cvss_v3_severity": "Critical", "scenario": "AV:N - The vulnerable loop is entered only from `cifs_demultiplex_thread()` processing an unsolicited SMB2 lease-break frame received from the remote SMB server over TCP/445, which routinely traverses the internet (e.g. Azure Files and other cloud SMB shares). A malicious or compromised server, or an on-path attacker injecting into the stream, delivers the trigger entirely as network data.\nAC:L - The attacker controls both sides of the race \u2014 it forces session teardown (session-expired/user-session-deleted status codes, TCP reset driving reconnect, DFS IPC churn) and then floods lease-break notifications \u2014 and it can stall the SMB2 LOGOFF reply so the session lingers in SES_EXITING on `smb_ses_list` for the entire request timeout, making the window arbitrarily wide and repeatable.\nPR:N - Unsolicited oplock/lease-break frames bypass `smb2_verify_signature()` entirely and the handler ignores SessionId/TreeId, matching only on the attacker-supplied LeaseKey, so no credentials on the client and no authenticated SMB session are needed to reach the vulnerable traversal.\nUI:N - In the realistic deployment \u2014 a persistent cifs mount from fstab, autofs, or a container volume \u2014 the connection already exists, and the compromised server or on-path injector triggers the code path with no action from any local user.\nS:U - The use-after-free corrupts kernel heap memory belonging to the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Walking a torn-down session's `tcon_list` and `pending_opens` dereferences freed slab objects whose contents the attacker can groom via heap spraying, turning `tcon->cfids`, `open->tlink`, and `open->lease_key` into attacker-influenced pointers that yield a kernel memory read primitive.\nI:H - The path writes into the freed memory \u2014 `spin_lock(&tcon->open_file_lock)`, `cifs_stats_inc()` counter increments, and `cifs_get_tlink()` refcount bumps \u2014 and later frees/queues work (`queue_work(cifsiod_wq, &cfid->lease_break)`) through sprayed pointers, giving heap corruption and control-flow hijacking potential.\nA:H - Dereferencing freed `cifs_ses`/`cifs_tcon` state from the demultiplex kernel thread readily produces an oops or panic, and because the trigger is a repeatable unauthenticated network frame the attacker can crash the client at will." } } }