An update of the linux package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - smb: client: restrict implied bcc[0] exemption to responses without data area smb2_check_message() has a     long-standing quirk that accepts a response whose calculated length is one byte larger than the bytes     actually received (server can return one byte more due to implied bcc[0]). This was introduced to     accommodate servers that omit the trailing bcc[0] overlap byte when no data area is present. However, the     exemption is applied unconditionally, regardless of whether the command actually carries a data area     (has_smb2_data_area[]). When a response with a data area is subject to the +1 exemption, the reported data     can extend one byte beyond the bytes actually received, yet smb2_check_message() still accepts it. The     subsequent decoder then reads past the end of the receive buffer. This is reachable during NEGOTIATE and     SESSION_SETUP, before the session is established. The resulting out-of-bounds reads are visible under     KASAN when mounting against a non-conforming server; both the SPNEGO/negTokenInit and the NTLMSSP     challenge decoders are affected: BUG: KASAN: slab-out-of-bounds in asn1_ber_decoder+0x16a7/0x1b00 Read of     size 1 at addr ffff8880084d67c0 by task mount.cifs/81 CPU: 1 UID: 0 PID: 81 Comm: mount.cifs Not tainted     7.1.0-rc6 #1 Call Trace: <TASK> dump_stack_lvl+0x4e/0x70 print_report+0x157/0x4c9 kasan_report+0xce/0x100     asn1_ber_decoder+0x16a7/0x1b00 decode_negTokenInit+0x19/0x30 SMB2_negotiate+0x31d9/0x4c90     cifs_negotiate_protocol+0x1f2/0x3f0 cifs_get_smb_ses+0x93f/0x17e0 cifs_mount_get_session+0x7f/0x3a0     cifs_mount+0xb4/0xcf0 cifs_smb3_do_mount+0x23a/0x1500 smb3_get_tree+0x3b0/0x630 vfs_get_tree+0x82/0x2d0     fc_mount+0x10/0x1b0 path_mount+0x50d/0x1de0 __x64_sys_mount+0x20b/0x270 do_syscall_64+0xee/0x590     entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Allocated by task 85: kmem_cache_alloc_noprof+0x106/0x380     mempool_alloc_noprof+0x116/0x1e0 cifs_small_buf_get+0x31/0x80 allocate_buffers+0x10d/0x2b0     cifs_demultiplex_thread+0x1d5/0x1d50 kthread+0x2c6/0x390 ret_from_fork+0x36e/0x5a0     ret_from_fork_asm+0x1a/0x30 The buggy address is located 0 bytes to the right of allocated 448-byte region     [ffff8880084d6600, ffff8880084d67c0) which belongs to the cache cifs_small_rq of size 448 BUG: KASAN:
    slab-out-of-bounds in kmemdup_noprof+0x36/0x50 Read of size 329 at addr ffff88800726c678 by task     mount.cifs/89 CPU: 0 UID: 0 PID: 89 Comm: mount.cifs Tainted: G B 7.1.0-rc6 #1 Call Trace: <TASK>     dump_stack_lvl+0x4e/0x70 print_report+0x157/0x4c9 kasan_report+0xce/0x100 kasan_check_range+0x10f/0x1e0
    __asan_memcpy+0x23/0x60 kmemdup_noprof+0x36/0x50 decode_ntlmssp_challenge+0x457/0x680     SMB2_sess_auth_rawntlmssp_negotiate+0x6f0/0xcb0 SMB2_sess_setup+0x219/0x4f0 cifs_setup_session+0x248/0xaf0     cifs_get_smb_ses+0xf79/0x17e0 cifs_mount_get_session+0x7f/0x3a0 cifs_mount+0xb4/0xcf0     cifs_smb3_do_mount+0x23a/0x1500 smb3_get_tree+0x3b0/0x630 vfs_get_tree+0x82/0x2d0 fc_mount+0x10/0x1b0     path_mount+0x50d/0x1de0 __x64_sys_mount+0x20b/0x270 do_syscall_64+0xee/0x590     entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Allocated by task 93: kmem_cache_alloc_noprof+0x106/0x380     mempool_alloc_noprof+0x116/0x1e0 cifs_small_buf_get+0x31/0x80 allocate_buffers+0x10d/0x2b0     cifs_demultiplex_thread+0x1d5/0x1d50 kthread+0x2c6/0x390 ret_from_fork+0x36e/0x5a0     ret_from_fork_asm+0x1a/0x30 The buggy address is located 120 bytes inside of allocated 448-byte region     [ffff88800726c600, ffff88800726c7c0) which belongs to the cache cifs_small_rq of size 448 Restrict the +1     exemption to responses that have no data area, so that it still covers the bcc[0] omission it was meant     for. When a data area is present, the +1 discrepancy instead means the reported data length overruns the
    ---truncated--- (CVE-2026-64448)

Note that Nessus relies on the presence of the package as reported by the vendor.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-099699 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    smb: client: restrict implied bcc[0] exemption to responses without data area

    smb2_check_message() has a long-standing quirk that accepts a response     whose calculated length is one byte larger than the bytes actually     received (server can return one byte more due to implied bcc[0]).
    This was introduced to accommodate servers that omit the trailing bcc[0]     overlap byte when no data area is present.

    However, the exemption is applied unconditionally, regardless of whether     the command actually carries a data area (has_smb2_data_area[]).  When a     response with a data area is subject to the +1 exemption, the reported     data can extend one byte beyond the bytes actually received, yet     smb2_check_message() still accepts it.  The subsequent decoder then reads     past the end of the receive buffer.  This is reachable during NEGOTIATE     and SESSION_SETUP, before the session is established.

    The resulting out-of-bounds reads are visible under KASAN when mounting     against a non-conforming server; both the SPNEGO/negTokenInit and the     NTLMSSP challenge decoders are affected:

      BUG: KASAN: slab-out-of-bounds in asn1_ber_decoder+0x16a7/0x1b00       Read of size 1 at addr ffff8880084d67c0 by task mount.cifs/81       CPU: 1 UID: 0 PID: 81 Comm: mount.cifs Not tainted 7.1.0-rc6 #1       Call Trace:
       <TASK>        dump_stack_lvl+0x4e/0x70        print_report+0x157/0x4c9        kasan_report+0xce/0x100        asn1_ber_decoder+0x16a7/0x1b00        decode_negTokenInit+0x19/0x30        SMB2_negotiate+0x31d9/0x4c90        cifs_negotiate_protocol+0x1f2/0x3f0        cifs_get_smb_ses+0x93f/0x17e0        cifs_mount_get_session+0x7f/0x3a0        cifs_mount+0xb4/0xcf0        cifs_smb3_do_mount+0x23a/0x1500        smb3_get_tree+0x3b0/0x630        vfs_get_tree+0x82/0x2d0        fc_mount+0x10/0x1b0        path_mount+0x50d/0x1de0
       __x64_sys_mount+0x20b/0x270        do_syscall_64+0xee/0x590        entry_SYSCALL_64_after_hwframe+0x77/0x7f        </TASK>       Allocated by task 85:
       kmem_cache_alloc_noprof+0x106/0x380        mempool_alloc_noprof+0x116/0x1e0        cifs_small_buf_get+0x31/0x80        allocate_buffers+0x10d/0x2b0        cifs_demultiplex_thread+0x1d5/0x1d50        kthread+0x2c6/0x390        ret_from_fork+0x36e/0x5a0        ret_from_fork_asm+0x1a/0x30       The buggy address is located 0 bytes to the right of        allocated 448-byte region [ffff8880084d6600, ffff8880084d67c0)        which belongs to the cache cifs_small_rq of size 448

      BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x36/0x50       Read of size 329 at addr ffff88800726c678 by task mount.cifs/89       CPU: 0 UID: 0 PID: 89 Comm: mount.cifs Tainted: G    B      7.1.0-rc6 #1       Call Trace:
       <TASK>        dump_stack_lvl+0x4e/0x70        print_report+0x157/0x4c9        kasan_report+0xce/0x100        kasan_check_range+0x10f/0x1e0
       __asan_memcpy+0x23/0x60        kmemdup_noprof+0x36/0x50        decode_ntlmssp_challenge+0x457/0x680        SMB2_sess_auth_rawntlmssp_negotiate+0x6f0/0xcb0        SMB2_sess_setup+0x219/0x4f0        cifs_setup_session+0x248/0xaf0        cifs_get_smb_ses+0xf79/0x17e0        cifs_mount_get_session+0x7f/0x3a0        cifs_mount+0xb4/0xcf0        cifs_smb3_do_mount+0x23a/0x1500        smb3_get_tree+0x3b0/0x630        vfs_get_tree+0x82/0x2d0        fc_mount+0x10/0x1b0        path_mount+0x50d/0x1de0
       __x64_sys_mount+0x20b/0x270        do_syscall_64+0xee/0x590        entry_SYSCALL_64_after_hwframe+0x77/0x7f        </TASK>       Allocated by task 93:
       kmem_cache_alloc_noprof+0x106/0x380        mempool_alloc_noprof+0x116/0x1e0        cifs_small_buf_get+0x31/0x80        allocate_buffers+0x10d/0x2b0        cifs_demultiplex_thread+0x1d5/0x1d50        kthread+0x2c6/0x390        ret_from_fork+0x36e/0x5a0        ret_from_fork_asm+0x1a/0x30       The buggy address is located 120 bytes inside of        allocated 448-byte region [ffff88800726c600, ffff88800726c7c0)        which belongs to the cache cifs_small_rq of size 448

    Restrict the +1 exemption to responses that have no data area, so that     it still covers the bcc[0] omission it was meant for.  When a data area     is present, the +1 discrepancy instead means the reported data length     overruns the
    ---truncated---

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
329325	Photon OS 5.0: Linux PHSA-2026-5.0-0928	Nessus	PhotonOS Local Security Checks	7/24/2026	10/14/2026	high
329904	Linux Distros Unpatched Vulnerability : CVE-2026-64448	Nessus	Misc.	7/25/2026	10/13/2026	high
336675	Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099699)	Nessus	Unity Linux Local Security Checks	8/17/2026	8/17/2026	high

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