CVE-2025-21734

Out-of-bounds memory access via offset-blind page calculation

Published Feb 27, 2025 · Updated Aug 5, 2026

Out-of-bounds memory access in Linux fastrpc allows local users to trigger a kernel memory issue via a non-registered buffer. The driver derives copied-buffer page boundaries from absolute addresses without applying the buffer offset, then passes an improper, potentially out-of-bounds page size to the remote subsystem. A low-privileged local context and a non-registered buffer are required; the Linux CNA does not specify whether the memory issue causes a crash or enables code execution.

CVSS severity7.8
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds memory access in Linux fastrpc allows local users to trigger a kernel memory issue via a non-registered buffer. The driver derives copied-buffer page boundaries from absolute addresses without applying the buffer offset, then passes an improper, potentially out-of-bounds page size to the remote subsystem. A low-privileged local context and a non-registered buffer are required; the Linux CNA does not specify whether the memory issue causes a crash or enables code execution.

The record

CVE
CVE-2025-21734
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <24a79c6bc8de763f7c50f4f84f8b0c183bc25a51
  2. Affected versionversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c0464bad0e85fcd5d47e4297d1e410097c979e55
  3. Affected versionversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c3f7161123fcbdc64e90119ccce292d8b66281c4
  4. Affected versionversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c56ba3ea8e3c9a69a992aad18f7a65e43e51d623
  5. Affected versionversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <e966eae72762ecfdbdb82627e2cda48845b9dd66
  6. Affected versionversion=5.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <24a79c6bc8de763f7c50f4f84f8b0c183bc25a51; version=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c0464bad0e85fcd5d47e4297d1e410097c979e55; version=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c3f7161123fcbdc64e90119ccce292d8b66281c4; version=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <c56ba3ea8e3c9a69a992aad18f7a65e43e51d623; version=02b45b47fbe84e23699bb6bdc74d4c2780e282b4 <e966eae72762ecfdbdb82627e2cda48845b9dd66; version=5.2

Published CVSS scores

7.8Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

No sourced classifications are available.

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo