CVE-2026-89716

Kernel crash via unchecked deflate winbits

Published Sep 11, 2026 · Updated Sep 11, 2026

Improper input validation in Linux 6.16 zram allows local users with zram configuration access to crash the kernel via deflate parameters. The deflate_setup_params function passes an unchecked user-supplied winbits value to zlib_deflate_workspacesize, whose range assertion triggers BUG_ON for invalid values. Reaching the fault requires privileged local writes to zram algorithm_params and device initialization; successful exploitation interrupts the host by crashing the kernel.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux 6.16 zram allows local users with zram configuration access to crash the kernel via deflate parameters. The deflate_setup_params function passes an unchecked user-supplied winbits value to zlib_deflate_workspacesize, whose range assertion triggers BUG_ON for invalid values. Reaching the fault requires privileged local writes to zram algorithm_params and device initialization; successful exploitation interrupts the host by crashing the kernel.

The record

CVE
CVE-2026-89716
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 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=6.16
  2. Affected versionversion=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <923578d0f0d0703c3db61ab35dc37075ae53b0bd
  3. Affected versionversion=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <e23fac4ab2a5728386477b98a402a1042b21bffb
  4. Affected versionversion=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <ec7607ac4717ff521c9c1e9d8271c26293345513

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.16; version=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <923578d0f0d0703c3db61ab35dc37075ae53b0bd; version=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <e23fac4ab2a5728386477b98a402a1042b21bffb; version=dc75a0d93bd5a1c64104efb4ec680463afbdd755 <ec7607ac4717ff521c9c1e9d8271c26293345513

Published CVSS scores

No CVSS assessment is available in this record.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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