Detections
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CentOS 9 : kernel-5.14.0-708.el9

medium Nessus Plugin ID 316888

Synopsis

The remote CentOS host is missing one or more security updates for kernel.

Description

The remote CentOS Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the kernel-5.14.0-708.el9 build changelog.

 - In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path. (CVE-2026-31684)

 - In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive.
 Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().
 (CVE-2026-43284)

 - In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: strictly check for maximum number of actions The maximum number of flowtable hardware offload actions in IPv6 is: * ethernet mangling (4 payload actions, 2 for each ethernet address) * SNAT (4 payload actions) * DNAT (4 payload actions) * Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing) for QinQ. * Redirect (1 action) Which makes 17, while the maximum is 16. But act_ct supports for tunnels actions too.
 Note that payload action operates at 32-bit word level, so mangling an IPv6 address takes 4 payload actions. Update flow_action_entry_next() calls to check for the maximum number of supported actions. While at it, rise the maximum number of actions per flow from 16 to 24 so this works fine with IPv6 setups.
 (CVE-2026-43329)

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

Solution

Update the CentOS 9 Stream kernel package.

See Also

https://kojihub.stream.centos.org/koji/buildinfo?buildID=111486

Plugin Details

Severity: Medium

ID: 316888

File Name: centos9_kernel-5_14_0-708_111486.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 5/27/2026

Updated: 5/27/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 10.0

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 4

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2026-31684

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5.3

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

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

Vulnerability Information

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

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/CentOS/release, Host/CentOS/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/20/2026

Vulnerability Publication Date: 4/25/2026

Reference Information

CVE: CVE-2026-31684, CVE-2026-43284, CVE-2026-43329