LiveActive security incident?Get immediate response
CVE Record

CVE-2023-53391: shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

In the Linux kernel, the following vulnerability has been resolved: shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs As the ramfs-based tmpfs uses ramfs_init_fs_context() for the init_fs_context method, which allocates fc->s_fs_info, use ramfs_kill_sb() to free it and avoid a memory leak.

MediumCVSS 5.5Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-53391 is a Linux kernel memory leak in ramfs-based tmpfs cleanup. A local low-privileged user may be able to trigger repeated leaks, creating an availability risk. The cited record rates it medium, with high availability impact and no confidentiality or integrity impact.

Executive priority

Treat this as a routine but real availability issue. It does not indicate remote compromise or data exposure from the supplied evidence, but affected shared Linux systems should be patched through normal kernel maintenance because local users can potentially degrade service availability.

Technical view

The bug is in shmem/tmpfs superblock teardown: ramfs-based tmpfs used ramfs_init_fs_context(), which allocates fc->s_fs_info, but did not use ramfs_kill_sb() to free it. The fix changes the kill_sb method to ramfs_kill_sb(). CVSS is 5.5: local, low complexity, low privileges, no user interaction, availability high.

Likely exposure

Exposure is likely limited to Linux systems running affected kernel versions listed in the CVE data, including lines around 5.10.188, 5.15.121, 6.1.39, 6.4.4, and 6.5. Distribution backports may change practical exposure, so package-level vendor status must be checked.

Exploitation context

The bundle does not show CISA KEV listing or any cited evidence of active exploitation. The CVSS vector indicates local access with low privileges is required. Impact is denial of service through resource exhaustion, not data theft or code execution.

Researcher notes

The key evidence is the kernel fix rationale: ramfs_init_fs_context() allocates s_fs_info, and ramfs_kill_sb() is needed to release it. The source bundle does not provide a reproducer, exploit report, CWE mapping, or distribution-specific fixed package versions.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixed packages.
  • Prioritize shared or multi-user Linux systems if affected.
  • Apply normal reboot or live-patching procedures after kernel update.
  • Monitor memory pressure until affected systems are patched.

Validation and detection

  • Inventory kernel versions across Linux assets.
  • Compare running kernels against vendor advisories and the CVE affected data.
  • Confirm the ramfs_kill_sb() fix is present in deployed kernel sources or changelogs.
  • Verify patched systems boot into the expected fixed kernel.
  • Review monitoring for unexplained kernel memory growth on affected hosts.
Prepared
Confidence
high
Sources
7

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.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2023-53391 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
3Timeline events
1ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2023-53391Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc3b1b1cbf002e65a3cabd479e68b5f35886a26db, c3b1b1cbf002e65a3cabd479e68b5f35886a26db, c3b1b1cbf002e65a3cabd479e68b5f35886a26db, c3b1b1cbf002e65a3cabd479e68b5f35886a26db, c3b1b1cbf002e65a3cabd479e68b5f35886a26dbunaffected
LinuxLinux2.6.30, 0, 5.10.188, 5.15.121, 6.1.39, 6.4.4, 6.5affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.