In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: refresh tcphdr after skb_ensure_writable synproxy_tstamp_adjust() rewrites the TCP timestamp option in place and then patches the TCP checksum via inet_proto_csum_replace4() on the caller-supplied tcphdr pointer. Both ipv4_synproxy_hook() and ipv6_synproxy_hook() obtain that pointer with skb_header_pointer() before calling in, so it may either alias skb->head directly or point at the caller's on-stack _tcph buffer. Between obtaining the pointer and using it, the function calls skb_ensure_writable(skb, optend), which on a cloned or non-linear skb invokes pskb_expand_head() and frees the old skb->head. After that point the cached th is stale: caller (ipv[46]_synproxy_hook) th = skb_header_pointer(skb, ..., &_tcph) synproxy_tstamp_adjust(skb, protoff, th, ...) skb_ensure_writable(skb, optend) pskb_expand_head() /* kfree(old skb->head) */ ... inet_proto_csum_replace4(&th->check, ...) /* writes into freed head, or into the caller's stack copy leaving the on-wire checksum stale */ The option bytes are written through skb->data and are fine; only the checksum update goes through th and so lands in the wrong place. The result is either a write into freed slab memory or a packet leaving with a checksum that does not match its payload. Fix by re-deriving th from skb->data + protoff immediately after skb_ensure_writable() succeeds, so the subsequent checksum update targets the linear, writable header.

The remote AlmaLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:57252 advisory.

    * kernel: netfilter: nf_conntrack_h323: fix OOB read in decode_choice() (CVE-2026-43233)
      * kernel: drm/amdkfd: Fix out-of-bounds write in kfd_event_page_set() (CVE-2026-43206)
      * kernel: drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline     Management v4 (CVE-2026-43237)
      * kernel: udf: fix partition descriptor append bookkeeping (CVE-2026-45991)
      * kernel: drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 (CVE-2026-45878)
      * kernel: ip6_gre: Use cached t->net in ip6erspan_changelink() (CVE-2026-46120)
      * kernel: sched/psi: fix race between file release and pressure write (CVE-2026-52991)
      * kernel: drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11 (CVE-2026-53143)
      * kernel: drm/amd/display: Clamp VBIOS HDMI retimer register count to array size (CVE-2026-53136)
      * kernel: mm/huge_memory: update file PMD counter before folio_put() (CVE-2026-53189)
      * kernel: drm/amd/display: Use krealloc_array() in dal_vector_reserve() (CVE-2026-53329)
      * kernel: drm/i915/gem: Fix phys BO pread/pwrite with offset (CVE-2026-53356)
      * kernel: drm/amdgpu: zero-initialize GART table on allocation (CVE-2026-53374)
      * kernel: drm/i915: Fix potential UAF in TTM object purge (CVE-2026-63884)
      * kernel: netfilter: synproxy: refresh tcphdr after skb_ensure_writable (CVE-2026-64007)
      * kernel: memfd: deny writeable mappings when implying SEAL_WRITE (CVE-2026-63952)
      * kernel: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()     (CVE-2026-63888)
      * kernel: drm/amdgpu: fix amdgpu_hmm_range_get_pages (CVE-2026-63879)
      * kernel: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot (CVE-2026-64048)
      * kernel: drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async     (CVE-2026-64219)
      * kernel: smb: client: fix double-free in SMB2_open() replay (CVE-2026-64382)
      * kernel: smb: client: mask server-provided mode to 07777 in modefromsid (CVE-2026-64379)
      * kernel: smb: client: fix query_info() replay double-free (CVE-2026-64386)
      * kernel: posix-cpu-timers: Prevent UAF caused by non-leader exec() race (CVE-2026-64560)
      * kernel: smb: client: validate DFS referral PathConsumed (CVE-2026-68343)
      * kernel: smb/client: handle overlapping allocated ranges in fallocate (CVE-2026-68388)


    Bug Fix(es) and Enhancement(s):

      * kernel 5.14.0-687.5.1.el9_8 breaks wifi when using FIPS (JIRA:AlmaLinux-181065)
      * vhost: reset the vring metadata cache on vring reconfiguration [almalinux-9.8.z]     (JIRA:AlmaLinux-224549)
      * cifs: smb1 directory listings from xp server returning EINVAL and EIO [almalinux-9.8.z]     (JIRA:AlmaLinux-235811)

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

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

The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-57252 advisory.

    - smb: client: validate DFS referral PathConsumed (CKI Backport Bot) [RHEL-237668] {CVE-2026-68343}
    - posix-cpu-timers: Prevent UAF caused by non-leader exec() race (Waiman Long) [RHEL-227844]     {CVE-2026-64560}
    - posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path (Waiman Long) [RHEL-227844]     {CVE-2026-64370}
    - smb/client: handle overlapping allocated ranges in fallocate (CKI Backport Bot) [RHEL-236207]     {CVE-2026-68388}
    - smb: client: mask server-provided mode to 07777 in modefromsid (CKI Backport Bot) [RHEL-234528]     {CVE-2026-64379}
    - sched/psi: fix race between file release and pressure write (Waiman Long) [RHEL-232554] {CVE-2026-52991}
    - smb: client: fix query_info() replay double-free (CKI Backport Bot) [RHEL-234121] {CVE-2026-64386}
    - smb: client: fix double-free in SMB2_open() replay (CKI Backport Bot) [RHEL-234107] {CVE-2026-64382}
    - mm/huge_memory: update file PMD counter before folio_put() (Luiz Capitulino) [RHEL-231225]     {CVE-2026-53189}
    - net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot (CKI Backport Bot) [RHEL-230090]     {CVE-2026-64048}
    - ip6_gre: Use cached t->net in ip6erspan_changelink(). (CKI Backport Bot) [RHEL-180144] {CVE-2026-46120}
    - scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd() (Maurizio Lombardi)     [RHEL-213222] {CVE-2026-63888}
    - drm/amdgpu: fix amdgpu_hmm_range_get_pages (Jose Exposito) [RHEL-222614] {CVE-2026-63879}
    - drm/amd/display: Use krealloc_array() in dal_vector_reserve() (CKI Backport Bot) [RHEL-222668]     {CVE-2026-53329}
    - drm/amd/display: Clamp VBIOS HDMI retimer register count to array size (CKI Backport Bot) [RHEL-222683]     {CVE-2026-53136}
    - drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11 (CKI Backport Bot)     [RHEL-222703] {CVE-2026-53143}
    - drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 (CKI Backport Bot) [RHEL-222718]     {CVE-2026-45878}
    - drm/i915: Fix potential UAF in TTM object purge (CKI Backport Bot) [RHEL-222742] {CVE-2026-63884}
    - drm/i915/gem: Fix phys BO pread/pwrite with offset (CKI Backport Bot) [RHEL-222748] {CVE-2026-53356}
    - drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async (CKI     Backport Bot) [RHEL-222571] {CVE-2026-64219}
    - drm/amdgpu: zero-initialize GART table on allocation (CKI Backport Bot) [RHEL-222647] {CVE-2026-53374}
    - drm/amdkfd: Fix out-of-bounds write in kfd_event_page_set() (CKI Backport Bot) [RHEL-221333]     {CVE-2026-43206}
    - drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management v7 (CKI     Backport Bot) [RHEL-221368] {CVE-2026-43237}
    - drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management v4 (CKI     Backport Bot) [RHEL-221368] {CVE-2026-43237}
    - netfilter: nf_conntrack_h323: fix OOB read in decode_choice() (CKI Backport Bot) [RHEL-230625]     {CVE-2026-43233}
    - netfilter: synproxy: refresh tcphdr after skb_ensure_writable (CKI Backport Bot) [RHEL-228909]     {CVE-2026-64007}
    - memfd: deny writeable mappings when implying SEAL_WRITE (Luiz Capitulino) [RHEL-228523] {CVE-2026-63952}

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

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

The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:57252 advisory.

    * kernel: netfilter: nf_conntrack_h323: fix OOB read in decode_choice() (CVE-2026-43233)

    * kernel: drm/amdkfd: Fix out-of-bounds write in kfd_event_page_set() (CVE-2026-43206)

    * kernel: drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management     v4 (CVE-2026-43237)

    * kernel: udf: fix partition descriptor append bookkeeping (CVE-2026-45991)

    * kernel: drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 (CVE-2026-45878)

    * kernel: ip6_gre: Use cached t->net in ip6erspan_changelink() (CVE-2026-46120)

    * kernel: sched/psi: fix race between file release and pressure write (CVE-2026-52991)

    * kernel: drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11 (CVE-2026-53143)

    * kernel: drm/amd/display: Clamp VBIOS HDMI retimer register count to array size (CVE-2026-53136)

    * kernel: mm/huge_memory: update file PMD counter before folio_put() (CVE-2026-53189)

    * kernel: drm/amd/display: Use krealloc_array() in dal_vector_reserve() (CVE-2026-53329)

    * kernel: drm/i915/gem: Fix phys BO pread/pwrite with offset (CVE-2026-53356)

    * kernel: drm/amdgpu: zero-initialize GART table on allocation (CVE-2026-53374)

    * kernel: drm/i915: Fix potential UAF in TTM object purge (CVE-2026-63884)

    * kernel: netfilter: synproxy: refresh tcphdr after skb_ensure_writable (CVE-2026-64007)

    * kernel: memfd: deny writeable mappings when implying SEAL_WRITE (CVE-2026-63952)

    * kernel: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()     (CVE-2026-63888)

    * kernel: drm/amdgpu: fix amdgpu_hmm_range_get_pages (CVE-2026-63879)

    * kernel: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot (CVE-2026-64048)

    * kernel: drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async     (CVE-2026-64219)

    * kernel: smb: client: fix double-free in SMB2_open() replay (CVE-2026-64382)

    * kernel: smb: client: mask server-provided mode to 07777 in modefromsid (CVE-2026-64379)

    * kernel: smb: client: fix query_info() replay double-free (CVE-2026-64386)

    * kernel: posix-cpu-timers: Prevent UAF caused by non-leader exec() race (CVE-2026-64560)

    * kernel: smb: client: validate DFS referral PathConsumed (CVE-2026-68343)

    * kernel: smb/client: handle overlapping allocated ranges in fallocate (CVE-2026-68388)

    Bug Fix(es) and Enhancement(s):

    * kernel 5.14.0-687.5.1.el9_8 breaks wifi when using FIPS  (JIRA:Rocky Linux-181065)

    * vhost: reset the vring metadata cache on vring reconfiguration [rhel-9.8.z] (JIRA:Rocky Linux-224549)

    * cifs: smb1 directory listings from xp server returning EINVAL and EIO [rhel-9.8.z] (JIRA:Rocky     Linux-235811)

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

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

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:57252 advisory.

    The kernel packages contain the Linux kernel, the core of any Linux operating system.

    Security Fix(es):

    * kernel: netfilter: nf_conntrack_h323: fix OOB read in decode_choice() (CVE-2026-43233)

    * kernel: drm/amdkfd: Fix out-of-bounds write in kfd_event_page_set() (CVE-2026-43206)

    * kernel: drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management     v4 (CVE-2026-43237)

    * kernel: udf: fix partition descriptor append bookkeeping (CVE-2026-45991)

    * kernel: drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 (CVE-2026-45878)

    * kernel: ip6_gre: Use cached t->net in ip6erspan_changelink() (CVE-2026-46120)

    * kernel: sched/psi: fix race between file release and pressure write (CVE-2026-52991)

    * kernel: drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11 (CVE-2026-53143)

    * kernel: drm/amd/display: Clamp VBIOS HDMI retimer register count to array size (CVE-2026-53136)

    * kernel: mm/huge_memory: update file PMD counter before folio_put() (CVE-2026-53189)

    * kernel: drm/amd/display: Use krealloc_array() in dal_vector_reserve() (CVE-2026-53329)

    * kernel: drm/i915/gem: Fix phys BO pread/pwrite with offset (CVE-2026-53356)

    * kernel: drm/amdgpu: zero-initialize GART table on allocation (CVE-2026-53374)

    * kernel: drm/i915: Fix potential UAF in TTM object purge (CVE-2026-63884)

    * kernel: netfilter: synproxy: refresh tcphdr after skb_ensure_writable (CVE-2026-64007)

    * kernel: memfd: deny writeable mappings when implying SEAL_WRITE (CVE-2026-63952)

    * kernel: scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()     (CVE-2026-63888)

    * kernel: drm/amdgpu: fix amdgpu_hmm_range_get_pages (CVE-2026-63879)

    * kernel: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot (CVE-2026-64048)

    * kernel: drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async     (CVE-2026-64219)

    * kernel: smb: client: fix double-free in SMB2_open() replay (CVE-2026-64382)

    * kernel: smb: client: mask server-provided mode to 07777 in modefromsid (CVE-2026-64379)

    * kernel: smb: client: fix query_info() replay double-free (CVE-2026-64386)

    * kernel: posix-cpu-timers: Prevent UAF caused by non-leader exec() race (CVE-2026-64560)

    * kernel: smb: client: validate DFS referral PathConsumed (CVE-2026-68343)

    * kernel: smb/client: handle overlapping allocated ranges in fallocate (CVE-2026-68388)

    Bug Fix(es) and Enhancement(s):

    * kernel 5.14.0-687.5.1.el9_8 breaks wifi when using FIPS  (JIRA:RHEL-181065)

    * vhost: reset the vring metadata cache on vring reconfiguration [rhel-9.8.z] (JIRA:RHEL-224549)

    * cifs: smb1 directory listings from xp server returning EINVAL and EIO [rhel-9.8.z] (JIRA:RHEL-235811)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-100110 advisory.

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

    netfilter: synproxy: refresh tcphdr after skb_ensure_writable

    synproxy_tstamp_adjust() rewrites the TCP timestamp option in place     and then patches the TCP checksum via inet_proto_csum_replace4() on     the caller-supplied tcphdr pointer.  Both ipv4_synproxy_hook() and     ipv6_synproxy_hook() obtain that pointer with skb_header_pointer()     before calling in, so it may either alias skb->head directly or     point at the caller's on-stack _tcph buffer.

    Between obtaining the pointer and using it, the function calls     skb_ensure_writable(skb, optend), which on a cloned or non-linear     skb invokes pskb_expand_head() and frees the old skb->head.  After     that point the cached th is stale:

        caller (ipv[46]_synproxy_hook)           th = skb_header_pointer(skb, ..., &_tcph)           synproxy_tstamp_adjust(skb, protoff, th, ...)             skb_ensure_writable(skb, optend)               pskb_expand_head()        /* kfree(old skb->head) */             ...
            inet_proto_csum_replace4(&th->check, ...)                                         /* writes into freed head, or                                            into the caller's stack copy                                            leaving the on-wire checksum                                            stale */

    The option bytes are written through skb->data and are fine; only     the checksum update goes through th and so lands in the wrong     place.  The result is either a write into freed slab memory or a     packet leaving with a checksum that does not match its payload.

    Fix by re-deriving th from skb->data + protoff immediately after     skb_ensure_writable() succeeds, so the subsequent checksum update     targets the linear, writable header.

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.

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.

  - netfilter: synproxy: refresh tcphdr after skb_ensure_writable synproxy_tstamp_adjust() rewrites the TCP     timestamp option in place and then patches the TCP checksum via inet_proto_csum_replace4() on the caller-     supplied tcphdr pointer. Both ipv4_synproxy_hook() and ipv6_synproxy_hook() obtain that pointer with     skb_header_pointer() before calling in, so it may either alias skb->head directly or point at the caller's     on-stack _tcph buffer. Between obtaining the pointer and using it, the function calls     skb_ensure_writable(skb, optend), which on a cloned or non-linear skb invokes pskb_expand_head() and frees     the old skb->head. After that point the cached th is stale: caller (ipv[46]_synproxy_hook) th =     skb_header_pointer(skb, ..., &_tcph) synproxy_tstamp_adjust(skb, protoff, th, ...)     skb_ensure_writable(skb, optend) pskb_expand_head() /* kfree(old skb->head) */ ...
    inet_proto_csum_replace4(&th->check, ...) /* writes into freed head, or into the caller's stack copy     leaving the on-wire checksum stale */ The option bytes are written through skb->data and are fine; only     the checksum update goes through th and so lands in the wrong place. The result is either a write into     freed slab memory or a packet leaving with a checksum that does not match its payload. Fix by re-deriving     th from skb->data + protoff immediately after skb_ensure_writable() succeeds, so the subsequent checksum     update targets the linear, writable header. (CVE-2026-64007)

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

ID	Name	Product	Family	Type	Severity
340747	AlmaLinux 9 : kernel (ALSA-2026:57252)	Nessus	Alma Linux Local Security Checks	Local	high
340681	Ubuntu 24.04 LTS / 26.04 LTS / Pro Realtime 24.04 LTS : Linux kernel (NVIDIA) vulnerabilities (USN-8663-1)	Nessus	Ubuntu Local Security Checks	Local	high
340045	Ubuntu 26.04 LTS : Linux kernel (NVIDIA BaseOS) vulnerabilities (USN-8664-1)	Nessus	Ubuntu Local Security Checks	Local	high
338722	Oracle Linux 9 : kernel (ELSA-2026-57252)	Nessus	Oracle Linux Local Security Checks	Local	high
338679	RockyLinux 9 : kernel (RLSA-2026:57252)	Nessus	Rocky Linux Local Security Checks	Local	high
338239	RHEL 9 : kernel (RHSA-2026:57252)	Nessus	Red Hat Local Security Checks	Local	high
336716	Unity Linux 20.1050e Security Update: kernel (UTSA-2026-100110)	Nessus	Unity Linux Local Security Checks	Local	critical
333941	Photon OS 5.0: Linux PHSA-2026-5.0-92-0926	Nessus	PhotonOS Local Security Checks	Local	high
333762	Photon OS 5.0: Linux PHSA-2026-5.0-92-0895	Nessus	PhotonOS Local Security Checks	Local	high
329326	Photon OS 5.0: Linux PHSA-2026-5.0-0926	Nessus	PhotonOS Local Security Checks	Local	high
328499	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.15-2026-110 (ALASKERNEL-5.15-2026-110)	Nessus	Amazon Linux Local Security Checks	Local	medium
328493	Amazon Linux 2023 : bpftool6.12, kernel6.12, kernel6.12-devel (ALAS2023-2026-1968)	Nessus	Amazon Linux Local Security Checks	Local	high
328121	Linux Distros Unpatched Vulnerability : CVE-2026-64007	Nessus	Misc.	Local	critical
327380	Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1924)	Nessus	Amazon Linux Local Security Checks	Local	high
325574	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.10-2026-124 (ALASKERNEL-5.10-2026-124)	Nessus	Amazon Linux Local Security Checks	Local	high
322944	Photon OS 5.0: Linux PHSA-2026-5.0-0895	Nessus	PhotonOS Local Security Checks	Local	high
322087	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1881)	Nessus	Amazon Linux Local Security Checks	Local	high

Detections

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CVE-2026-64007

critical

Tenable Plugins

high

high

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critical

high

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