CVE-2026-12039Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution
Updated under an hour ago ()
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It affects Docker Sandboxes. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist.
- CVSS
- 5.7 MEDIUM (v4.0, CNA)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
- Weakness (CWE)
- CWE-923
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Docker
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 13, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.