CentOS 9:kernel-5.14.0-742.el9

high Nessus プラグイン ID 343845

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概要

リモートの CentOS ホストに 1 つ以上の kernel 用セキュリティ更新プログラムがありません。

説明

リモートのCentOS Linux 9ホストには、kernel-5.14.0-742.el9ビルド変更ログに記載されている複数の脆弱性の影響を受けるパッケージがインストールされています。

- Linux カーネルでは、以下の脆弱性が解決されています: xen/privcmd: fix double free via VMA splitting privcmd_vm_ops defines .close (privcmd_close), but neither .may_split nor .open. When userspace does a partial munmap() on a privcmd mapping, the kernel splits the VMA via __split_vma(). Since may_split is NULL, the split is allowed. vm_area_dup() copies vm_private_data (a pages array allocated in alloc_empty_pages()) into the new VMA without any fixup, because there is no .open callback. Both VMAs now point to the same pages array. When the unmapped portion is closed, privcmd_close() calls: - xen_unmap_domain_gfn_range() - xen_free_unpopulated_pages() - kvfree(pages) The surviving VMA still holds the dangling pointer. When it is later destroyed, the same sequence runs again, which leads to a double free. Fix this issue by adding a .may_split callback denying the VMA split. This is XSA-487 / CVE-2026-31787 (CVE-2026-31787)

- Linux カーネルでは、以下の脆弱性が解決されています: Buffer overflow in drivers/xen/sys-hypervisor.c The build id returned by HYPERVISOR_xen_version(XENVER_build_id) is neither NUL terminated nor a string. The first causes a buffer overflow as sprintf in buildid_show will read and copy till it finds a NUL. 00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P| 00000010 b9 a8 01 42 6f 2e 32 |...Bo.2| 00000017 So use a memcpy instead of sprintf to have the correct value: 00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q.....eGR..q.P| 00000010 b9 a8 01 42 |...B| 00000014 (the above have a hack to embed a zero inside and check it's returned correctly). This is XSA-485 / CVE-2026-31786 (CVE-2026-31786)

- Linux カーネルでは、以下の脆弱性が解決されています: sctp: diag: reject stale associations in dump_one path The SCTP exact sock_diag lookup can hold a transport reference, block on lock_sock(sk), and then resume after sctp_association_free() has marked the association dead and freed its bind address list. When that happens, inet_assoc_attr_size() and inet_diag_msg_sctpasoc_fill() can still dereference association state that is no longer valid for reporting. In particular, inet_diag_msg_sctpasoc_fill() may read an empty bind-address list as a real sctp_sockaddr_entry and trigger an out-of-bounds read from unrelated association memory. Reject the association after taking the socket lock if it has been reaped or detached from the endpoint, and report the lookup as stale. This keeps the exact dump-one path from formatting torn association state. (CVE-2026-52917)

- Linux カーネルでは、以下の脆弱性が解決されています: NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr nfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a netaddr4 from a GETDEVICEINFO multipath-DS body, then immediately calls strrchr(buf, '.') to locate the port separator. Both decodes use xdr_stream_decode_string_dup(), and the current code checks only nlen < 0 / rlen < 0 before dereferencing the returned string. When the on-wire opaque has length zero, xdr_stream_decode_opaque_inline() returns 0 and xdr_stream_decode_string_dup() falls through to its *str = NULL; return ret tail, leaving buf NULL with a return value of 0. The < 0 check does not catch this, and the next line is strrchr(NULL, '.'), a kernel NULL pointer dereference reachable from any pNFS-flexfile client mounted against a malicious or compromised metadata server. Reject the zero-length cases explicitly so the decoder fails with -EBADMSG (treated as a malformed GETDEVICEINFO body) instead of panicking the client. (CVE-2026-53391)

- Linux カーネルでは、以下の脆弱性が解決されています: NFSv4/flexfiles: reject zero filehandle version count ff_layout_alloc_lseg() decodes the filehandle-version array count from the flexfiles layout body. The value is used as the count for kzalloc_objs(), and the current code only rejects NULL. A zero count yields ZERO_SIZE_PTR, which can be stored in dss_info->fh_versions even though later flexfiles paths assume that at least one filehandle version exists. Reject fh_count == 0 before the allocation, matching the existing zero version_count validation in the flexfiles GETDEVICEINFO parser. A QEMU/KASAN run with a malformed flexfiles layout hit: KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750 ff_layout_encode_layoutreturn+0x683/0x970 nfs4_xdr_enc_layoutreturn+0x278/0x3a0 Kernel panic - not syncing: Fatal exception The patched kernel rejects the malformed layout without KASAN/oops/panic, and a valid fh_count=1 regression still opens, reads, and unmounts cleanly. (CVE-2026-53392)

Nessus はこれらの問題をテストしておらず、代わりにアプリケーションが自己報告するバージョン番号にのみ依存していることに注意してください。

ソリューション

CentOS 9 Stream kernel パッケージを更新してください。

参考資料

https://kojihub.stream.centos.org/koji/buildinfo?buildID=128312

プラグインの詳細

深刻度: High

ID: 343845

ファイル名: centos9_kernel-5_14_0-742_128312.nasl

バージョン: 1.1

タイプ: Local

エージェント: unix

ファミリー: CentOS Local Security Checks

公開日: 2026/9/8

更新日: 2026/9/8

サポートされているセンサー: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

リスク情報

VPR

リスクファクター: High

スコア: 7.6

パーセンタイル: 98.37

CVSS v2

リスクファクター: Medium

基本値: 6.8

現状値: 5

ベクトル: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS スコアのソース: CVE-2026-31787

CVSS v3

リスクファクター: High

基本値: 7.8

現状値: 6.8

ベクトル: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

現状ベクトル: CVSS:3.0/E:U/RL:O/RC:C

脆弱性情報

CPE: cpe:/a:centos:centos:9, p-cpe:/a:centos:centos:kernel-64k-core, p-cpe:/a:centos:centos:kernel-64k-debug-core, p-cpe:/a:centos:centos:kernel-64k-debug-devel-matched, p-cpe:/a:centos:centos:kernel-64k-debug-devel, p-cpe:/a:centos:centos:kernel-64k-debug-modules-core, p-cpe:/a:centos:centos:kernel-64k-debug-modules-extra, p-cpe:/a:centos:centos:kernel-64k-debug-modules-internal, p-cpe:/a:centos:centos:kernel-64k-debug-modules-partner, p-cpe:/a:centos:centos:kernel-64k-debug-modules, p-cpe:/a:centos:centos:kernel-64k-debug, p-cpe:/a:centos:centos:kernel-64k-devel-matched, p-cpe:/a:centos:centos:kernel-64k-devel, p-cpe:/a:centos:centos:kernel-64k-modules-core, p-cpe:/a:centos:centos:kernel-64k-modules-extra, p-cpe:/a:centos:centos:kernel-64k-modules-internal, p-cpe:/a:centos:centos:kernel-64k-modules-partner, p-cpe:/a:centos:centos:kernel-64k-modules, p-cpe:/a:centos:centos:kernel-64k, p-cpe:/a:centos:centos:kernel-abi-stablelists, p-cpe:/a:centos:centos:kernel-core, p-cpe:/a:centos:centos:kernel-cross-headers, p-cpe:/a:centos:centos:kernel-debug-core, p-cpe:/a:centos:centos:kernel-debug-devel-matched, p-cpe:/a:centos:centos:kernel-debug-devel, p-cpe:/a:centos:centos:kernel-debug-modules-core, p-cpe:/a:centos:centos:kernel-debug-modules-extra, p-cpe:/a:centos:centos:kernel-debug-modules-internal, p-cpe:/a:centos:centos:kernel-debug-modules-partner, p-cpe:/a:centos:centos:kernel-debug-modules, p-cpe:/a:centos:centos:kernel-debug-uki-virt-addons, p-cpe:/a:centos:centos:kernel-debug-uki-virt, p-cpe:/a:centos:centos:kernel-debug, p-cpe:/a:centos:centos:kernel-devel-matched, p-cpe:/a:centos:centos:kernel-devel, p-cpe:/a:centos:centos:kernel-headers, p-cpe:/a:centos:centos:kernel-kmap-internal, p-cpe:/a:centos:centos:kernel-modules-core, p-cpe:/a:centos:centos:kernel-modules-extra, p-cpe:/a:centos:centos:kernel-modules-internal, p-cpe:/a:centos:centos:kernel-modules-partner, p-cpe:/a:centos:centos:kernel-modules, p-cpe:/a:centos:centos:kernel-rt-64k-core, p-cpe:/a:centos:centos:kernel-rt-64k-debug-core, p-cpe:/a:centos:centos:kernel-rt-64k-debug-devel-matched, p-cpe:/a:centos:centos:kernel-rt-64k-debug-devel, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-core, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-extra, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-partner, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules, p-cpe:/a:centos:centos:kernel-rt-64k-debug, p-cpe:/a:centos:centos:kernel-rt-64k-devel-matched, p-cpe:/a:centos:centos:kernel-rt-64k-devel, p-cpe:/a:centos:centos:kernel-rt-64k-modules-core, p-cpe:/a:centos:centos:kernel-rt-64k-modules-extra, p-cpe:/a:centos:centos:kernel-rt-64k-modules-internal, p-cpe:/a:centos:centos:kernel-rt-64k-modules-partner, p-cpe:/a:centos:centos:kernel-rt-64k-modules, p-cpe:/a:centos:centos:kernel-rt-64k, p-cpe:/a:centos:centos:kernel-rt-core, p-cpe:/a:centos:centos:kernel-rt-debug-core, p-cpe:/a:centos:centos:kernel-rt-debug-devel-matched, p-cpe:/a:centos:centos:kernel-rt-debug-devel, p-cpe:/a:centos:centos:kernel-rt-debug-modules-core, p-cpe:/a:centos:centos:kernel-rt-debug-modules-extra, p-cpe:/a:centos:centos:kernel-rt-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-debug-modules-partner, p-cpe:/a:centos:centos:kernel-rt-debug-modules, p-cpe:/a:centos:centos:kernel-rt-debug, p-cpe:/a:centos:centos:kernel-rt-devel-matched, p-cpe:/a:centos:centos:kernel-rt-devel, p-cpe:/a:centos:centos:kernel-rt-modules-core, p-cpe:/a:centos:centos:kernel-rt-modules-extra, p-cpe:/a:centos:centos:kernel-rt-modules-internal, p-cpe:/a:centos:centos:kernel-rt-modules-partner, p-cpe:/a:centos:centos:kernel-rt-modules, p-cpe:/a:centos:centos:kernel-rt, p-cpe:/a:centos:centos:kernel-selftests-internal, p-cpe:/a:centos:centos:kernel-tools-libs-devel, p-cpe:/a:centos:centos:kernel-tools-libs, p-cpe:/a:centos:centos:kernel-tools, p-cpe:/a:centos:centos:kernel-uki-virt-addons, p-cpe:/a:centos:centos:kernel-uki-virt, p-cpe:/a:centos:centos:kernel-zfcpdump-core, p-cpe:/a:centos:centos:kernel-zfcpdump-devel-matched, p-cpe:/a:centos:centos:kernel-zfcpdump-devel, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-core, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-extra, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-internal, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-partner, p-cpe:/a:centos:centos:kernel-zfcpdump-modules, p-cpe:/a:centos:centos:kernel-zfcpdump, p-cpe:/a:centos:centos:kernel, p-cpe:/a:centos:centos:libperf-devel, p-cpe:/a:centos:centos:libperf, p-cpe:/a:centos:centos:perf, p-cpe:/a:centos:centos:python3-perf, p-cpe:/a:centos:centos:rtla, p-cpe:/a:centos:centos:rv

必要な KB アイテム: Host/local_checks_enabled, Host/cpu, Host/CentOS/release, Host/CentOS/rpm-list

エクスプロイトの容易さ: No known exploits are available

パッチ公開日: 2026/9/2

脆弱性公開日: 2026/4/30

参照情報

CVE: CVE-2026-31786, CVE-2026-31787, CVE-2026-52917, CVE-2026-53391, CVE-2026-53392, CVE-2026-53397, CVE-2026-53399, CVE-2026-63800, CVE-2026-63801, CVE-2026-63824, CVE-2026-63887, CVE-2026-63971, CVE-2026-64298, CVE-2026-64490, CVE-2026-68117, CVE-2026-68145, CVE-2026-68300, CVE-2026-68315, CVE-2026-68376, CVE-2026-74581