NVD / CVE Program· CNA Linux

CVE-2023-53123: PCI: s390: Fix use-after-free of PCI resources with per-function hotplug

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 437bb839e36cc9f35adc6d2a2bf113b7a0fc9985, a2410d0c3d2d714ed968a135dfcbed6aa3ff7027, ab909509850b27fd39b8ba99e44cda39dbc3858c.

Low priority for now. Upgrade to Linux Linux 437bb839e36cc9f35adc6d2a2bf113b7a0fc9985, a2410d0c3d2d714ed968a135dfcbed6aa3ff7027, ab909509850b27fd39b8ba99e44cda39dbc3858c or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: PCI: s390: Fix use-after-free of PCI resources with per-function hotplug On s390 PCI functions may be hotplugged individually even when they belong to a multi-function device. In particular on an SR-IOV device VFs may be removed and later re-added. In commit a50297cf8235 ("s390/pci: separate zbus creation from scanning") it was missed however that struct pci_bus and struct zpci_bus's resource list retained a reference to the PCI functions MMIO resources even though those resources are released and freed on hot-unplug. These stale resources may subsequently be claimed when the PCI function re-appears resulting in use-after-free. One idea of fixing this use-after-free in s390 specific code that was investigated was to simply keep resources around from the moment a PCI function first appeared until the whole virtual PCI bus created for a multi-function device disappears. The problem with this however is that due to the requirement of artificial MMIO addreesses (address cookies) extra logic is then needed to keep the address cookies compatible on re-plug. At the same time the MMIO resources semantically belong to the PCI function so tying their lifecycle to the function seems more logical. Instead a simpler approach is to remove the resources of an individually hot-unplugged PCI function from the PCI bus's resource list while keeping the resources of other PCI functions on the PCI bus untouched. This is done by introducing pci_bus_remove_resource() to remove an individual resource. Similarly the resource also needs to be removed from the struct zpci_bus's resource list. It turns out however, that there is really no need to add the MMIO resources to the struct zpci_bus's resource list at all and instead we can simply use the zpci_bar_struct's resource pointer directly.

Memory safety

BDU:2026-05794

Published: May 2, 2025
Updated: Nov 5, 2026
EPSS: 0.1% · 8th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 5.13affected
- a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 and later · before 437bb839e36cc9f35adc6d2a2bf113b7a0fc9985affected · git
- a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 and later · before a2410d0c3d2d714ed968a135dfcbed6aa3ff7027affected · git
- a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 and later · before b99ebf4b62774e690e73a551cf5fbf6f219bdd96affected · git
- a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 and later · before ab909509850b27fd39b8ba99e44cda39dbc3858caffected · git
- before 5.13not affected · semver
- 5.15.104 and later · up to and including 5.15.*not affected · semver
- 6.1.21 and later · up to and including 6.1.*not affected · semver
- 6.2.8 and later · up to and including 6.2.*not affected · semver
- 6.3 and laternot affected · original_commit_for_fix

Affected versions · NVD (4)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel5.13 and later · before 5.15.104
linux linux kernel5.16 and later · before 6.1.21
linux linux kernel6.2 and later · before 6.2.8
linux linux kernel6.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.25-1	6.1.25-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
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Published before and after this one in the same product

← EarlierCVE-2023-53120May 2, 2025 · scsi: mpi3mr: Fix config page DMA memory leak
22Monitor
← EarlierCVE-2023-53121May 2, 2025 · tcp: tcp_make_synack() can be called from process context
22Monitor
Later →CVE-2023-53124May 2, 2025 · scsi: mpt3sas: Fix NULL pointer access in mpt3sas_transport_port_add()
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	437bb839e36cc9f35adc6d2a2bf113b7a0fc9985	Vendor (CNA)
Linux Linux	a2410d0c3d2d714ed968a135dfcbed6aa3ff7027	Vendor (CNA)
Linux Linux	ab909509850b27fd39b8ba99e44cda39dbc3858c	Vendor (CNA)
Linux Linux	b99ebf4b62774e690e73a551cf5fbf6f219bdd96	Vendor (CNA)
debian:linux	6.1.25-1 · Debian:12	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log (2)

SSVC exploitation— → noneNov 5, 2026, 10:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/437bb839e36cc9f35adc6d2a2bf113b7a0fc9985

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records