Linux Kernel: NULL Pointer Dereference (CVE-2022-48895)
Published Sources: BSI, CVE.org, EUVD
What is affected, what to do
In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Don't unregister on shutdown Michael Walle says he noticed the following stack trace while performing a shutdown with "reboot -f". He suggests he got "lucky" and just hit the correct spot for the reboot while there was a packet transmission in flight.
Update Linux Kernel to version 6.1.7, Linux Kernel to version 6.2.
- Affected
- Linux Kernel
lt 6.1..6.1.7
- Linux Kernel
- Fixed in
- Linux Kernel
6.1.7 - Linux Kernel
6.2
- Linux Kernel
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Metrics
5.5
XIEM Effective CVSS
Highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
5.5
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: BSI, CVE.org, EUVD
0.2 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 11.1
Show all metrics
- Severity
- Medium
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 34.39 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 5.5 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 5.5
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.2 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 11.1
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · not automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 10 September 2024
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Don't unregister on shutdown Michael Walle says he noticed the following stack trace while performing a shutdown with "reboot -f". He suggests he got "lucky" and just hit the correct spot for the reboot while there was a packet transmission in flight. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098 CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 6.1.0-rc5-00088-gf3600ff8e322 #1930 Hardware name: Kontron KBox A-230-LS (DT) pc : iommu_get_dma_domain+0x14/0x20 lr : iommu_dma_map_page+0x9c/0x254 Call trace: iommu_get_dma_domain+0x14/0x20 dma_map_page_attrs+0x1ec/0x250 enetc_start_xmit+0x14c/0x10b0 enetc_xmit+0x60/0xdc dev_hard_start_xmit+0xb8/0x210 sch_direct_xmit+0x11c/0x420 __dev_queue_xmit+0x354/0xb20 ip6_finish_output2+0x280/0x5b0 __ip6_finish_output+0x15c/0x270 ip6_output+0x78/0x15c NF_HOOK.constprop.0+0x50/0xd0 mld_sendpack+0x1bc/0x320 mld_ifc_work+0x1d8/0x4dc process_one_work+0x1e8/0x460 worker_thread+0x178/0x534 kthread+0xe0/0xe4 ret_from_fork+0x10/0x20 Code: d503201f f9416800 d503233f d50323bf (f9404c00) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Oops: Fatal exception in interrupt This appears to be reproducible when the board has a fixed IP address, is ping flooded from another host, and "reboot -f" is used. The following is one more manifestation of the issue: $ reboot -f kvm: exiting hardware virtualization cfg80211: failed to load regulatory.db arm-smmu 5000000.iommu: disabling translation sdhci-esdhc 2140000.mmc: Removing from iommu group 11 sdhci-esdhc 2150000.mmc: Removing from iommu group 12 fsl-edma 22c0000.dma-controller: Removing from iommu group 17 dwc3 3100000.usb: Removing from iommu group 9 dwc3 3110000.usb: Removing from iommu group 10 ahci-qoriq 3200000.sata: Removing from iommu group 2 fsl-qdma 8380000.dma-controller: Removing from iommu group 20 platform f080000.display: Removing from iommu group 0 etnaviv-gpu f0c0000.gpu: Removing from iommu group 1 etnaviv etnaviv: Removing from iommu group 1 caam_jr 8010000.jr: Removing from iommu group 13 caam_jr 8020000.jr: Removing from iommu group 14 caam_jr 8030000.jr: Removing from iommu group 15 caam_jr 8040000.jr: Removing from iommu group 16 fsl_enetc 0000:00:00.0: Removing from iommu group 4 arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications arm-smmu 5000000.iommu: GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000 fsl_enetc 0000:00:00.1: Removing from iommu group 5 arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications arm-smmu 5000000.iommu: GFSR 0x80000002, GFSYNR0 0x00000002, GFSYNR1 0x00000429, GFSYNR2 0x00000000 arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications arm-smmu 5000000.iommu: GFSR 0x80000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000 fsl_enetc 0000:00:00.2: Removing from iommu group 6 fsl_enetc_mdio 0000:00:00.3: Removing from iommu group 8 mscc_felix 0000:00:00.5: Removing from iommu group 3 fsl_enetc 0000:00:00.6: Removing from iommu group 7 pcieport 0001:00:00.0: Removing from iommu group 18 arm-smmu 5000000.iommu: Blocked unknown Stream ID 0x429; boot with "arm-smmu.disable_bypass=0" to allow, but this may have security implications arm-smmu 5000000.iommu: GFSR 0x00000002, GFSYNR0 0x00000000, GFSYNR1 0x00000429, GFSYNR2 0x00000000 pcieport 0002:00:00.0: Removing from iommu group 19 Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a8 pc : iommu_get_dma_domain+0x14/0x20 lr : iommu_dma_unmap_page+0x38/0xe0 Call trace: iommu_get_dma_domain+0x14/0x20 dma_unmap_page_attrs+0x38/0x1d0 en ---truncated---
Source: BSI CSAF, BSI WID Portal, cvelistv5, ENISA EUVD, NVD (NIST)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Linux | Linux |
|
|
Vendors and products
Affected operating systems
| Linux | linux | linux_kernel | 6.2 |
| Linux | linux | linux_kernel | — |
References & sources
- git.kernel.orgstable/c/a1b9c7b1978aacf4b2f33e34bde1e2bb80b8497aeuvd, Patch
- git.kernel.orgstable/c/ce31e6ca68bd7639bd3e5ef97be215031842bbabeuvd, Patch
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<a href="https://intel.neosec.eu/en/cve/CVE-2022-48895"><img src="https://intel.neosec.eu/badge/cve/CVE-2022-48895.svg?lang=en" alt="CVE-2022-48895 – NEOSEC Intel" height="20"></a>