OESA-2026-4720: docker security update
Docker is an open source project to build, ship and run any application as a lightweight container. Security Fix(es):
Docker Engine classifies a registry hostname as insecure using an any-match DNS check. loadInsecureRegistries() injects 127.0.0.0/8 and ::1/128 as insecure CIDRs by default. isCIDRMatch resolves all of the hostname's addresses and returns true if a single address is in the insecure CIDR list. Because the transport re-dials the hostname rather than the CIDR-matching address, a DNS answer set of one loopback IP plus a non-loopback attacker IP disables certificate verification and enables HTTP fallback for the registry connection.(CVE-2026-92543)
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
openeuler/dockerto a version that resolves this vulnerability.Fixed in engine-18.09.0-358.oe2403sp3
Event History
Frequently Asked Questions
Are Docker Engine installations affected without explicitly configuring insecure registries?
Yes. The affected logic injects 127.0.0.0/8 and ::1/128 into the insecure CIDR list by default.
What conditions are needed to exploit this issue?
A registry hostname must resolve to an answer set containing at least one loopback address covered by the insecure CIDRs and a non-loopback attacker IP address. Docker then treats the hostname as insecure, while the transport re-dials the hostname rather than the loopback address that caused the match.
What is the security impact of a successful exploit?
Certificate verification can be disabled for the registry connection, and HTTP fallback can be enabled. This can allow a registry connection to use the non-loopback attacker address returned for the hostname.