CVE-2026-89579

Local privilege escalation via bloom-filter under-allocation

Published Sep 11, 2026 · Updated Sep 11, 2026

Out-of-bounds write in Linux allows local users with CAP_BPF to elevate privileges through crafted BPF bloom maps on 32-bit x86 kernels. bloom_map_alloc computes BITS_TO_BYTES(U32_MAX) with wrapping 32-bit arithmetic, allocates only the fixed object, and retains a U32_MAX mask. Subsequent bloom-map updates write beyond the allocation; signed bit indexes can also access memory before the bitset.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
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 write in Linux allows local users with CAP_BPF to elevate privileges through crafted BPF bloom maps on 32-bit x86 kernels. bloom_map_alloc computes BITS_TO_BYTES(U32_MAX) with wrapping 32-bit arithmetic, allocates only the fixed object, and retains a U32_MAX mask. Subsequent bloom-map updates write beyond the allocation; signed bit indexes can also access memory before the bitset.

The record

CVE
CVE-2026-89579
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
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=5.16
  2. Affected versionversion=9330986c03006ab1d33d243b7cfe598a7a3c1baa <11c1e836710dcba03e50454a4eedfdbaf8d3050e
  3. Affected versionversion=9330986c03006ab1d33d243b7cfe598a7a3c1baa <272fcb4ba6fab678db0eb966dc81c4c804bef64a
  4. Affected versionversion=9330986c03006ab1d33d243b7cfe598a7a3c1baa <3b7a13eccfcf97714ffc1ca6aa663d66d4a30e29
  5. Affected versionversion=9330986c03006ab1d33d243b7cfe598a7a3c1baa <dff481e12b3f127739f6a4ea7cef2c25dc12e056

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=5.16; version=9330986c03006ab1d33d243b7cfe598a7a3c1baa <11c1e836710dcba03e50454a4eedfdbaf8d3050e; version=9330986c03006ab1d33d243b7cfe598a7a3c1baa <272fcb4ba6fab678db0eb966dc81c4c804bef64a; version=9330986c03006ab1d33d243b7cfe598a7a3c1baa <3b7a13eccfcf97714ffc1ca6aa663d66d4a30e29; version=9330986c03006ab1d33d243b7cfe598a7a3c1baa <dff481e12b3f127739f6a4ea7cef2c25dc12e056

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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