CVE-2025-21778

Kernel crash via vmap-backed ring-buffer mmap

Published Feb 27, 2025 · Updated Aug 5, 2026

A kernel tracing flaw in affected Linux 6.12 and 6.13 builds and 6.14-rc1 through 6.14-rc2 allows local users to crash the kernel. The ring_buffer_map path passes vmap-backed persistent-buffer addresses through virt_to_page and then vm_insert_pages, which expects ordinary page-backed memory. Access to a reserve_mem-backed trace instance and its trace_pipe_raw file is required; invalid page handling can expose memory, corrupt kernel bookkeeping, wedge tracing, or panic the host.

CVSS severity7.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A kernel tracing flaw in affected Linux 6.12 and 6.13 builds and 6.14-rc1 through 6.14-rc2 allows local users to crash the kernel. The ring_buffer_map path passes vmap-backed persistent-buffer addresses through virt_to_page and then vm_insert_pages, which expects ordinary page-backed memory. Access to a reserve_mem-backed trace instance and its trace_pipe_raw file is required; invalid page handling can expose memory, corrupt kernel bookkeeping, wedge tracing, or panic the host.

The record

CVE
CVE-2025-21778
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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=6.12
  2. Affected versionversion=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <129fe718819cc5e24ea2f489db9ccd4371f0c6f6
  3. Affected versionversion=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <cf5aa560e5c7628b57c928741d7e6a9a0f6f0e67
  4. Affected versionversion=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <e8dff5f73912513fc9b52ab992d861517c9a9975

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <129fe718819cc5e24ea2f489db9ccd4371f0c6f6; version=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <cf5aa560e5c7628b57c928741d7e6a9a0f6f0e67; version=9b7bdf6f6ece6ea888cc7d2f02c00b403b66a119 <e8dff5f73912513fc9b52ab992d861517c9a9975

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Canonical UbuntuCVSS: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

T1499Endpoint Denial of Service

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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