CVE-2026-89783Network attack vector

Kernel memory overwrite via off-by-one secpath check

Published Sep 16, 2026 · Updated Sep 16, 2026

An out-of-bounds write in the Linux kernel xfrm6 IPv6 input path allows attackers to overwrite a kernel pointer slot via crafted protected packets. xfrm6_input_addr() applies an equality-based depth check that misses a preserved six-entry secpath, then increments sp->len while writing beyond the six-element xvec array. Reachability requires transport-mode XFRM reinjection plus an inner HAO option or type-2 routing header; the overwrite panics hosts configured with panic_on_warn.

CVSS severityUnavailable
Unscored
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

An out-of-bounds write in the Linux kernel xfrm6 IPv6 input path allows attackers to overwrite a kernel pointer slot via crafted protected packets. xfrm6_input_addr() applies an equality-based depth check that misses a preserved six-entry secpath, then increments sp->len while writing beyond the six-element xvec array. Reachability requires transport-mode XFRM reinjection plus an inner HAO option or type-2 routing header; the overwrite panics hosts configured with panic_on_warn.

The record

CVE
CVE-2026-89783
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
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=2.6.25
  2. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <0f679e0523ddfff3fb554336ceb874b0e51e9cd3
  3. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <48996649222e95008cdb98cd58579e3fc8e5ee06
  4. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc
  5. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <5f35a29a5eed3d80befd32050843ac88dea3d61a
  6. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <68e8737fe8e72f085c608cff322b3d2de8340af1
  7. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77
  8. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <91fc387f63c00ddfb5221127a17bac97549a8343
  9. Affected versionversion=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <bdcda866c89f9a8b1acdabf02d26cde9fbe501d8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.25; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <0f679e0523ddfff3fb554336ceb874b0e51e9cd3; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <48996649222e95008cdb98cd58579e3fc8e5ee06; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <5f35a29a5eed3d80befd32050843ac88dea3d61a; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <68e8737fe8e72f085c608cff322b3d2de8340af1; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <91fc387f63c00ddfb5221127a17bac97549a8343; version=9473e1f631de339c50bde1e3bd09e1045fe90fd5 <bdcda866c89f9a8b1acdabf02d26cde9fbe501d8

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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
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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