CVE-2026-43390

Privileged namespace disclosure via permissive listns check

Published May 8, 2026 · Updated May 8, 2026

Information disclosure in Linux Kernel 6.19 through 6.19.8 allows local users to enumerate other services' namespaces via listns(). The may_list_ns() function in kernel/nstree.c accepts CAP_SYS_ADMIN in a namespace owner and returns namespace identifiers instead of applying may_see_all_namespaces(). A caller with namespace-scoped CAP_SYS_ADMIN can discover peer-service namespace topology; no code execution, data modification, or service interruption is reported.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Linux Kernel 6.19 through 6.19.8 allows local users to enumerate other services' namespaces via listns(). The may_list_ns() function in kernel/nstree.c accepts CAP_SYS_ADMIN in a namespace owner and returns namespace identifiers instead of applying may_see_all_namespaces(). A caller with namespace-scoped CAP_SYS_ADMIN can discover peer-service namespace topology; no code execution, data modification, or service interruption is reported.

The record

CVE
CVE-2026-43390
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1613
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=6.19
  2. Affected versionversion=76b6f5dfb3fda76fce1f9990d6fa58adc711122b <0abd81645fc95ec6a9d4e4813000f22c5efc0ff4
  3. Affected versionversion=76b6f5dfb3fda76fce1f9990d6fa58adc711122b <8d76afe84fa2babf604b3c173730d4d2b067e361

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.19; version=76b6f5dfb3fda76fce1f9990d6fa58adc711122b <0abd81645fc95ec6a9d4e4813000f22c5efc0ff4; version=76b6f5dfb3fda76fce1f9990d6fa58adc711122b <8d76afe84fa2babf604b3c173730d4d2b067e361

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1613Container and Resource Discovery

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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