CVE-2026-89778Hinoki check available

Kernel out-of-bounds read via zisofs page overcount

Published Sep 16, 2026 · Updated Sep 16, 2026

Out-of-bounds access in Linux isofs zisofs handling allows attackers to trigger a kernel-memory read via a crafted ISO9660 image. The empty-block path in zisofs_uncompress_block() ignores poffset when reporting bytes produced, causing zisofs_fill_pages() to advance pages[] beyond its allocation. The path requires the image to be mounted and a compressed file to be read; the published reproducer reaches a KASAN slab-out-of-bounds fault.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Out-of-bounds access in Linux isofs zisofs handling allows attackers to trigger a kernel-memory read via a crafted ISO9660 image. The empty-block path in zisofs_uncompress_block() ignores poffset when reporting bytes produced, causing zisofs_fill_pages() to advance pages[] beyond its allocation. The path requires the image to be mounted and a compressed file to be read; the published reproducer reaches a KASAN slab-out-of-bounds fault.

The record

CVE
CVE-2026-89778
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=2.6.33
  2. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <68d4d3e78150c7ed7d1195af63ad1e6ace30c661
  3. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <85904076cece72ee3194646ad7ac8e6659d999aa
  4. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <8b994ac5778a725982fd6a8a3afcaa068d4a93e3
  5. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <9c6eace8d07e90f038c89eb3b756d65a7e259d48
  6. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a
  7. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <cd616aa0449a772a6956abf03358f0ff31720580
  8. Affected versionversion=59bc055211b8d266ab6089158058bf8268e02006 <f03425dcbe04aec3c27b9917e97d7d23a2908dda

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.33; version=59bc055211b8d266ab6089158058bf8268e02006 <68d4d3e78150c7ed7d1195af63ad1e6ace30c661; version=59bc055211b8d266ab6089158058bf8268e02006 <85904076cece72ee3194646ad7ac8e6659d999aa; version=59bc055211b8d266ab6089158058bf8268e02006 <8b994ac5778a725982fd6a8a3afcaa068d4a93e3; version=59bc055211b8d266ab6089158058bf8268e02006 <9c6eace8d07e90f038c89eb3b756d65a7e259d48; version=59bc055211b8d266ab6089158058bf8268e02006 <ad3249cdf9d4ba34bb8b1ff3956a4020fdfb5b0a; version=59bc055211b8d266ab6089158058bf8268e02006 <cd616aa0449a772a6956abf03358f0ff31720580; version=59bc055211b8d266ab6089158058bf8268e02006 <f03425dcbe04aec3c27b9917e97d7d23a2908dda

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
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

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Your stack

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