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CVE Record

CVE-2022-49995: writeback: avoid use-after-free after removing device

In the Linux kernel, the following vulnerability has been resolved: writeback: avoid use-after-free after removing device When a disk is removed, bdi_unregister gets called to stop further writeback and wait for associated delayed work to complete. However, wb_inode_writeback_end() may schedule bandwidth estimation dwork after this has completed, which can result in the timer attempting to access the just freed bdi_writeback. Fix this by checking if the bdi_writeback is alive, similar to when scheduling writeback work. Since this requires wb->work_lock, and wb_inode_writeback_end() may get called from interrupt, switch wb->work_lock to an irqsafe lock.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw can leave background writeback work pointing at freed memory after a disk is removed. The public record does not state real-world exploitation, CVSS score, or business impact. Organizations should treat it as a kernel stability and safety issue, especially on systems using removable or dynamically detached storage.

Executive priority

Medium operational priority until vendor guidance clarifies impact. There is no evidence of exploitation in the supplied sources, but kernel memory-safety bugs can affect system reliability and should be addressed through normal kernel patch management, with faster handling for storage-dynamic environments.

Technical view

The issue is a use-after-free in Linux writeback handling. After bdi_unregister waits for delayed writeback work, wb_inode_writeback_end() could schedule bandwidth-estimation delayed work that later accesses freed bdi_writeback memory. The fix checks whether the writeback structure is alive and changes wb->work_lock to an IRQ-safe lock.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds, particularly where disks or block devices can be removed or detached. The source bundle lists Linux kernel versions including 5.15, 5.15.64, 5.19.6, and 6.0, but complete distribution mapping is not provided.

Exploitation context

No cited source reports active exploitation, inclusion in CISA KEV, exploit availability, or a practical attack path. The trigger condition described is disk removal combined with writeback delayed work scheduling. Security impact beyond use-after-free is not established in the supplied sources.

Researcher notes

Evidence is limited to the CVE description and Linux stable commit references. The record lacks CVSS, CWE, exploitability analysis, and distro-specific affected package data. Avoid assuming privilege escalation or remote exploitation without additional vendor or researcher evidence.

Mitigation direction

  • Update to a Linux kernel containing the referenced stable fixes.
  • Check distribution vendor advisories for backported kernel packages.
  • Prioritize hosts with removable, hot-plugged, or dynamically detached storage.
  • Avoid unnecessary disk removal on unpatched systems where operationally feasible.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and cloud images.
  • Compare installed kernels against vendor advisories and referenced stable commits.
  • Identify systems using removable, hot-plugged, or dynamically detached block devices.
  • Confirm patched systems boot the intended kernel after maintenance.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2022-49995 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
4Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux45a2966fd64147518dc5bca25f447bd0fb5359ac, 45a2966fd64147518dc5bca25f447bd0fb5359ac, 45a2966fd64147518dc5bca25f447bd0fb5359acunaffected
LinuxLinux5.15, 0, 5.15.64, 5.19.6, 6.0affected
Weakness

CWE details

No CWE listed

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