CVE-2026-12539

ICMP egress bypass via missing authorizer restoration

Published Jun 18, 2026 · Updated Jun 18, 2026

Improper ICMP egress enforcement in Docker Sandboxes before 0.33.0 allows local users to bypass network policy after a daemon restart. On daemon restart, sbx rebuilds persisted networks from disk without reapplying the ICMP authorizer installed only during network creation. An untrusted sandbox workload can then reach arbitrary hosts for reconnaissance or data exfiltration over an ICMP covert channel, regardless of the allowlist.

CVSS severity5.7
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper ICMP egress enforcement in Docker Sandboxes before 0.33.0 allows local users to bypass network policy after a daemon restart. On daemon restart, sbx rebuilds persisted networks from disk without reapplying the ICMP authorizer installed only during network creation. An untrusted sandbox workload can then reach arbitrary hosts for reconnaissance or data exfiltration over an ICMP covert channel, regardless of the allowlist.

The record

CVE
CVE-2026-12539
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
Docker
Product
Docker Sandboxes
Classifications
CWE-665, CWE-923, T1048.003, T1018
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 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=0.14.0 <0.33.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Docker · Docker Sandboxesversion=0.14.0 <0.33.0

Published CVSS scores

5.7Docker Inc.CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-665Improper Initialization
CWE-923Improper Restriction of Communication Channel to Intended Endpoints
T1048.003Exfiltration Over Unencrypted Non-C2 Protocol
T1018Remote System 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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