Detections
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Linux Distros Unpatched Vulnerability : CVE-2025-40254

medium Nessus Plugin ID 277528

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

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

 - net: openvswitch: remove never-working support for setting nsh fields The validation of the set(nsh(...)) action is completely wrong. It runs through the nsh_key_put_from_nlattr() function that is the same function that validates NSH keys for the flow match and the push_nsh() action. However, the set(nsh(...)) has a very different memory layout. Nested attributes in there are doubled in size in case of the masked set(). That makes proper validation impossible. There is also confusion in the code between the 'masked' flag, that says that the nested attributes are doubled in size containing both the value and the mask, and the 'is_mask' that says that the value we're parsing is the mask. This is causing kernel crash on trying to write into mask part of the match with SW_FLOW_KEY_PUT() during validation, while validate_nsh() doesn't allocate any memory for it: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF:
 supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1c2383067 P4D 1c2383067 PUD 20b703067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 8 UID: 0 Kdump: loaded Not tainted 6.17.0-rc4+ #107 PREEMPT(voluntary) RIP: 0010:nsh_key_put_from_nlattr+0x19d/0x610 [openvswitch] Call Trace: <TASK> validate_nsh+0x60/0x90 [openvswitch] validate_set.constprop.0+0x270/0x3c0 [openvswitch]
 __ovs_nla_copy_actions+0x477/0x860 [openvswitch] ovs_nla_copy_actions+0x8d/0x100 [openvswitch] ovs_packet_cmd_execute+0x1cc/0x310 [openvswitch] genl_family_rcv_msg_doit+0xdb/0x130 genl_family_rcv_msg+0x14b/0x220 genl_rcv_msg+0x47/0xa0 netlink_rcv_skb+0x53/0x100 genl_rcv+0x24/0x40 netlink_unicast+0x280/0x3b0 netlink_sendmsg+0x1f7/0x430 ____sys_sendmsg+0x36b/0x3a0
 ___sys_sendmsg+0x87/0xd0 __sys_sendmsg+0x6d/0xd0 do_syscall_64+0x7b/0x2c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The third issue with this process is that while trying to convert the non-masked set into masked one, validate_set() copies and doubles the size of the OVS_KEY_ATTR_NSH as if it didn't have any nested attributes. It should be copying each nested attribute and doubling them in size independently. And the process must be properly reversed during the conversion back from masked to a non-masked variant during the flow dump. In the end, the only two outcomes of trying to use this action are either validation failure or a kernel crash. And if somehow someone manages to install a flow with such an action, it will most definitely not do what it is supposed to, since all the keys and the masks are mixed up. Fixing all the issues is a complex task as it requires re-writing most of the validation code. Given that and the fact that this functionality never worked since introduction, let's just remove it altogether. It's better to re-introduce it later with a proper implementation instead of trying to fix it in stable releases. (CVE-2025-40254)

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

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2025-40254

https://security-tracker.debian.org/tracker/CVE-2025-40254

Plugin Details

Severity: Medium

ID: 277528

File Name: unpatched_CVE_2025_40254.nasl

Version: 1.2

Type: local

Agent: unix

Family: Misc.

Published: 12/4/2025

Updated: 12/5/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 4.2

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

CVSS Score Source: CVE-2025-40254

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5.1

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:U/RL:U/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel-rt-selftests-internal, p-cpe:/a:redhat:enterprise_linux:kernel-modules-partner, p-cpe:/a:centos:centos:kernel-64k-debug-core, p-cpe:/a:centos:centos:kernel-headers, p-cpe:/a:centos:centos:kernel-rt-64k-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug, p-cpe:/a:centos:centos:kernel-64k-modules-internal, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules, p-cpe:/a:redhat:enterprise_linux:kernel-debug, p-cpe:/a:centos:centos:kernel-rt-modules-internal, cpe:/o:debian:debian_linux:14.0, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:centos:centos:libperf, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules, p-cpe:/a:centos:centos:kernel-rt-64k-debug-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-internal, p-cpe:/a:centos:centos:rv, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-core, p-cpe:/a:centos:centos:kernel-rt-64k-modules, p-cpe:/a:centos:centos:kernel-64k-debug, p-cpe:/a:debian:debian_linux:linux, p-cpe:/a:redhat:enterprise_linux:kernel, p-cpe:/a:centos:centos:kernel-rt-64k-debug-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-internal, p-cpe:/a:centos:centos:kernel-doc, p-cpe:/a:centos:centos:kernel-64k-debug-modules-extra, p-cpe:/a:centos:centos:kernel-tools-libs, p-cpe:/a:redhat:enterprise_linux:kernel-64k, p-cpe:/a:redhat:enterprise_linux:rtla, p-cpe:/a:centos:centos:kernel-debug-modules, p-cpe:/a:redhat:enterprise_linux:kernel-ipaclones-internal, p-cpe:/a:centos:centos:kernel-rt-debug-kvm, p-cpe:/a:centos:centos:kernel-rt-debug-devel, p-cpe:/a:centos:centos:kernel-64k-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-modules, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-tools, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules, p-cpe:/a:centos:centos:rtla, p-cpe:/a:centos:centos:kernel-64k-debug-devel, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-internal, p-cpe:/a:centos:centos:kernel-64k-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-core, p-cpe:/a:centos:centos:kernel-modules-extra, p-cpe:/a:centos:centos:kernel-cross-headers, p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt-addons, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules, p-cpe:/a:centos:centos:kernel-debug-uki-virt-addons, p-cpe:/a:centos:centos:kernel-zfcpdump, p-cpe:/a:redhat:enterprise_linux:kernel-abi-whitelists, p-cpe:/a:redhat:enterprise_linux:kernel-devel, p-cpe:/a:centos:centos:kernel-modules-extra-matched, p-cpe:/a:redhat:enterprise_linux:python3-perf, p-cpe:/a:centos:centos:kernel-rt-64k-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-partner, p-cpe:/a:centos:centos:kernel-64k-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel, p-cpe:/a:centos:centos:kernel-rt-64k-debug-devel-matched, p-cpe:/a:centos:centos:kernel-rt-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-core, p-cpe:/a:centos:centos:kernel-64k-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-selftests-internal, p-cpe:/a:redhat:enterprise_linux:bpftool, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-core, p-cpe:/a:centos:centos:kernel-rt-debug-devel-matched, p-cpe:/a:centos:centos:kernel-64k, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-core, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-internal, p-cpe:/a:centos:centos:bpftool, p-cpe:/a:centos:centos:kernel-core, p-cpe:/a:centos:centos:kernel-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug, p-cpe:/a:centos:centos:kernel-rt-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-internal, p-cpe:/a:centos:centos:kernel-rt-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-kvm, p-cpe:/a:centos:centos:kernel-rt-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-extra, p-cpe:/a:centos:centos:kernel-rt-modules-extra, p-cpe:/a:centos:centos:kernel-64k-debug-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs-devel, p-cpe:/a:redhat:enterprise_linux:kernel-cross-headers, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-extra, p-cpe:/a:centos:centos:kernel-tools-libs-devel, p-cpe:/a:centos:centos:kernel-64k-core, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel-matched, p-cpe:/a:centos:centos:kernel-rt-64k-modules-core, p-cpe:/a:redhat:enterprise_linux:rv, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:centos:centos:kernel-debug, p-cpe:/a:centos:centos:kernel-selftests-internal, p-cpe:/a:centos:centos:kernel-rt-64k-debug, p-cpe:/a:centos:centos:perf, p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-modules-core, p-cpe:/a:centos:centos:kernel, p-cpe:/a:centos:centos:kernel-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules, p-cpe:/a:centos:centos:kernel-rt-64k-modules-internal, p-cpe:/a:centos:centos:kernel-debug-uki-virt, p-cpe:/a:centos:centos:kernel-tools, p-cpe:/a:centos:centos:kernel-rt-debug, p-cpe:/a:centos:centos:kernel-modules-partner, p-cpe:/a:redhat:enterprise_linux:libperf-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-core, p-cpe:/a:centos:centos:kernel-zfcpdump-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-core, p-cpe:/a:centos:centos:libperf-devel, p-cpe:/a:centos:centos:kernel-zfcpdump-modules, p-cpe:/a:centos:centos:kernel-rt-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-64k-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-core, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:kernel-zfcpdump-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt, p-cpe:/a:redhat:enterprise_linux:libperf, p-cpe:/a:redhat:enterprise_linux:kernel-devel-matched, p-cpe:/a:centos:centos:kernel-64k-debug-modules, p-cpe:/a:centos:centos:kernel-modules, p-cpe:/a:redhat:enterprise_linux:kernel-modules-internal, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-extra, p-cpe:/a:centos:centos:kernel-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:perf, p-cpe:/a:redhat:enterprise_linux:kernel-abi-stablelists, p-cpe:/a:centos:centos:kernel-rt-modules, p-cpe:/a:centos:centos:kernel-abi-stablelists, p-cpe:/a:redhat:enterprise_linux:kernel-debug-core, p-cpe:/a:centos:centos:kernel-zfcpdump-devel, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-core, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-internal, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-partner, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-extra, p-cpe:/a:centos:centos:kernel-rt-debug-modules, p-cpe:/a:centos:centos:kernel-uki-virt, p-cpe:/a:centos:centos:kernel-rt-debug-modules-extra, p-cpe:/a:centos:centos:kernel-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-partner, p-cpe:/a:centos:centos:kernel-debug-core, p-cpe:/a:redhat:enterprise_linux:kernel-debug-uki-virt-addons, p-cpe:/a:redhat:enterprise_linux:kernel-selftests-internal, p-cpe:/a:centos:centos:kernel-rt-64k-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules, p-cpe:/a:centos:centos:kernel-rt-modules-core, 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-zfcpdump-modules-partner, p-cpe:/a:centos:centos:kernel-64k-devel, p-cpe:/a:redhat:enterprise_linux:kernel-headers, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-core, p-cpe:/a:centos:centos:kernel-rt-64k-devel, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-partner, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-64k-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-core, p-cpe:/a:centos:centos:kernel-ipaclones-internal, p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra-matched, p-cpe:/a:redhat:enterprise_linux:kernel-debug-uki-virt, p-cpe:/a:centos:centos:kernel-modules-core, p-cpe:/a:centos:centos:kernel-uki-virt-addons, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-doc, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-64k-core, p-cpe:/a:centos:centos:kernel-64k-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-internal, p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-partner, p-cpe:/a:centos:centos:kernel-abi-whitelists, p-cpe:/a:centos:centos:kernel-zfcpdump-modules-extra, p-cpe:/a:centos:centos:kernel-debug-modules-partner, p-cpe:/a:centos:centos:kernel-debug-modules-extra, p-cpe:/a:centos:centos:kernel-devel-matched, p-cpe:/a:centos:centos:kernel-rt, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug, p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-partner, p-cpe:/a:centos:centos:kernel-rt-modules-partner, p-cpe:/a:centos:centos:kernel-rt-64k-debug-modules, p-cpe:/a:centos:centos:python3-perf, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-internal, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-64k-modules-extra, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-devel, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel, p-cpe:/a:centos:centos:kernel-rt-debug-modules-partner, p-cpe:/a:centos:centos:kernel-debug-modules-internal, p-cpe:/a:centos:centos:kernel-rt-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-core, p-cpe:/a:centos:centos:kernel-modules-internal, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules, p-cpe:/a:centos:centos:kernel-rt-debug-core, p-cpe:/a:centos:centos:kernel-rt-64k

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 12/4/2025

Reference Information

CVE: CVE-2025-40254