CVE-2023-53391

Local service interruption via tmpfs mount memory leak

Published Sep 18, 2025 · Updated Sep 18, 2025

Memory leak in ramfs-based tmpfs in affected Linux kernel releases allows local users to exhaust memory through repeated mount cycles. The ramfs-based tmpfs uses ramfs_init_fs_context() to allocate fc->s_fs_info, but its kill_sb path calls kill_litter_super() without freeing that allocation. A local user with permission to create a user namespace and mount tmpfs can repeat mount and unmount operations until memory pressure interrupts service.

CVSS severity5.5
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in ramfs-based tmpfs in affected Linux kernel releases allows local users to exhaust memory through repeated mount cycles. The ramfs-based tmpfs uses ramfs_init_fs_context() to allocate fc->s_fs_info, but its kill_sb path calls kill_litter_super() without freeing that allocation. A local user with permission to create a user namespace and mount tmpfs can repeat mount and unmount operations until memory pressure interrupts service.

The record

CVE
CVE-2023-53391
Published
Sep 18, 2025
Updated
Sep 18, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.30
  2. Affected versionversion=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <1f34bf8b442c6d720e7fa6f15e8702427e48aea9
  3. Affected versionversion=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <36ce9d76b0a93bae799e27e4f5ac35478c676592
  4. Affected versionversion=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <487f229efea80c00dd7397547ec4f25fb8999d99
  5. Affected versionversion=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <5fada375113767b3b57f1b04f7a4fe64ffaa626f
  6. Affected versionversion=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <ebe07db840992a3886694ac3d303b06f4b70ce00

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.30; version=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <1f34bf8b442c6d720e7fa6f15e8702427e48aea9; version=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <36ce9d76b0a93bae799e27e4f5ac35478c676592; version=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <487f229efea80c00dd7397547ec4f25fb8999d99; version=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <5fada375113767b3b57f1b04f7a4fe64ffaa626f; version=c3b1b1cbf002e65a3cabd479e68b5f35886a26db <ebe07db840992a3886694ac3d303b06f4b70ce00

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.001OS Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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