CVE-2023-54095 — powerpc/iommu: Fix notifiers being shared by PCI and VIO buses
In the Linux kernel, the following vulnerability has been resolved: powerpc/iommu: Fix notifiers being shared by PCI and VIO buses fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both PCI and VIO buses. struct notifier_block is a linked list node, so this causes any notifiers later registered to either bus type to also be registered to the other since they share the same node. This causes issues in (at least) the vgaarb code, which registers a notifier for PCI buses. pci_notify() ends up being called on a vio device, converted with to_pci_dev() even though it's not a PCI device, and finally makes a bad access in vga_arbiter_add_pci_device() as discovered with KASAN: BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00 Read of size 4 at addr c000000264c26fdc by task swapper/0/1 Call Trace: dump_stack_lvl+0x1bc/0x2b8 (unreliable) print_report+0x3f4/0xc60 kasan_report+0x244/0x698 __asan_load4+0xe8/0x250 vga_arbiter_add_pci_device+0x60/0xe00 pci_notify+0x88/0x444 notifier_call_chain+0x104/0x320 blocking_notifier_call_chain+0xa0/0x140 device_add+0xac8/0x1d30 device_register+0x58/0x80 vio_register_device_node+0x9ac/0xce0 vio_bus_scan_register_devices+0xc4/0x13c __machine_initcall_pseries_vio_device_init+0x94/0xf0 do_one_initcall+0x12c/0xaa8 kernel_init_freeable+0xa48/0xba8 kernel_init+0x64/0x400 ret_from_kernel_thread+0x5c/0x64 Fix this by creating separate notifier_block structs for each bus type. [mpe: Add #ifdef to fix CONFIG_IBMVIO=n build]
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < dc0d107e624ca96aef6dd8722eb33ba3a6d157b0≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < 075a4dcdbc9a5ea793cb8ec8b78a6c0b7636fd52≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < 65bf8a196ba25cf65a858b5bb8de80f0aad76691≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < f08944e3c6962b00827de7263a9e20688e79ad84≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < a9ddbfed53465bc7c411231db32a488066c0c1be≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < f17d5efaafba3d5f02f0373f7c5f44711d676f3e≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < c46af58588253e5e4063bb5ddc78cd12fdf9e55d≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < 6670c65bf863cd0d44ca24d4c10ef6755b8d9529 and 2 more≥ d6b9a81b2a45786384f5bd3516bd6ddfb4b772c6 and < c37b6908f7b2bd24dcaaf14a180e28c9132b9c58version 3.6 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.0 | CVSS 3.1 | High | 1.0 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.0 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.0 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.16%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Affected products added · linux/linux
- Record published
- CVSS changed · 7.0
- Source status changed · → Deferred
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 15, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
11 on the record
- git.kernel.org/stable/c/c46af58588253e5e4063bb5ddc78cd12fdf9e55d
- github.com/advisories/GHSA-6v42-prqv-7q9g
- git.kernel.org/stable/c/f17d5efaafba3d5f02f0373f7c5f44711d676f3e
- git.kernel.org/stable/c/dc0d107e624ca96aef6dd8722eb33ba3a6d157b0
- git.kernel.org/stable/c/a9ddbfed53465bc7c411231db32a488066c0c1be
- nvd.nist.gov/vuln/detail/CVE-2023-54095
- git.kernel.org/stable/c/f08944e3c6962b00827de7263a9e20688e79ad84
- git.kernel.org/stable/c/c37b6908f7b2bd24dcaaf14a180e28c9132b9c58
- git.kernel.org/stable/c/65bf8a196ba25cf65a858b5bb8de80f0aad76691
- git.kernel.org/stable/c/6670c65bf863cd0d44ca24d4c10ef6755b8d9529
- git.kernel.org/stable/c/075a4dcdbc9a5ea793cb8ec8b78a6c0b7636fd52
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 11h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 11h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2023-54095 is "powerpc/iommu: Fix notifiers being shared by PCI and VIO buses", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.0 describes technical severity. EPSS 0.16% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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