CVE-2025-21680

Kernel memory corruption via excessive imix entries

Published Jan 31, 2025 · Updated Aug 5, 2026

Out-of-bounds access in Linux pktgen allows local users to corrupt kernel memory through a crafted imix configuration write. In net/core/pktgen.c, get_imix_entries accepts 21 size-and-weight pairs because its boundary check permits one entry beyond the 20-element imix_entries array. An ordinary local user can reach the procfs control through user and network namespaces; the overwrite can disclose adjacent memory, corrupt slab objects, or crash the kernel.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux pktgen allows local users to corrupt kernel memory through a crafted imix configuration write. In net/core/pktgen.c, get_imix_entries accepts 21 size-and-weight pairs because its boundary check permits one entry beyond the 20-element imix_entries array. An ordinary local user can reach the procfs control through user and network namespaces; the overwrite can disclose adjacent memory, corrupt slab objects, or crash the kernel.

The record

CVE
CVE-2025-21680
Published
Jan 31, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-129, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 31, 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

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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=5.15
  2. Affected versionversion=52a62f8603f97e720882c8f5aff2767ac6a11d5f <1a9b65c672ca9dc4ba52ca2fd54329db9580ce29
  3. Affected versionversion=52a62f8603f97e720882c8f5aff2767ac6a11d5f <3450092cc2d1c311c5ea92a2486daa2a33520ea5
  4. Affected versionversion=52a62f8603f97e720882c8f5aff2767ac6a11d5f <76201b5979768500bca362871db66d77cb4c225e
  5. Affected versionversion=52a62f8603f97e720882c8f5aff2767ac6a11d5f <7cde21f52042aa2e29a654458166b873d2ae66b3
  6. Affected versionversion=52a62f8603f97e720882c8f5aff2767ac6a11d5f <e5d24a7074dcd0c7e76b7e7e4efbbe7418d62486

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=52a62f8603f97e720882c8f5aff2767ac6a11d5f <1a9b65c672ca9dc4ba52ca2fd54329db9580ce29; version=52a62f8603f97e720882c8f5aff2767ac6a11d5f <3450092cc2d1c311c5ea92a2486daa2a33520ea5; version=52a62f8603f97e720882c8f5aff2767ac6a11d5f <76201b5979768500bca362871db66d77cb4c225e; version=52a62f8603f97e720882c8f5aff2767ac6a11d5f <7cde21f52042aa2e29a654458166b873d2ae66b3; version=52a62f8603f97e720882c8f5aff2767ac6a11d5f <e5d24a7074dcd0c7e76b7e7e4efbbe7418d62486

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NISTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1068Exploitation for Privilege Escalation

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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