Mobyproject: Security Vulnerabilities
Moby is an open source container framework developed by Docker Inc. that is distributed as Docker Engine, Mirantis Container Runtime, and various other downstream projects/products. In versions 28.2.0 through 28.3.2, when the firewalld service is reloaded it removes all iptables rules including those created by Docker. While Docker should automatically recreate these rules, versions before 28.3.3 fail to recreate the specific rules that block external access to containers. This means that after a firewalld reload, containers with ports published to localhost (like 127.0.0.1:8080) become accessible from remote machines that have network routing to the Docker bridge, even though they should only be accessible from the host itself. The vulnerability only affects explicitly published ports - unpublished ports remain protected. This issue is fixed in version 28.3.3.
CVSS Score
4.6
EPSS Score
0.0
Published
2025-07-30
Moby is an open source container framework developed by Docker Inc. that is distributed as Docker Engine, Mirantis Container Runtime, and various other downstream projects/products. A firewalld vulnerability affects Moby releases before 28.0.0. When firewalld reloads, Docker fails to re-create iptables rules that isolate bridge networks, allowing any container to access all ports on any other container across different bridge networks on the same host. This breaks network segmentation between containers that should be isolated, creating significant risk in multi-tenant environments. Only containers in --internal networks remain protected.
Workarounds include reloading firewalld and either restarting the docker daemon, re-creating bridge networks, or using rootless mode. Maintainers anticipate a fix for this issue in version 25.0.13.
CVSS Score
3.3
EPSS Score
0.0
Published
2025-07-30
moby through v25.0.3 has a Race Condition vulnerability in the streamformatter package which can be used to trigger multiple concurrent write operations resulting in data corruption or application crashes.
CVSS Score
8.1
EPSS Score
0.002
Published
2024-11-29
moby v25.0.0 - v26.0.2 is vulnerable to NULL Pointer Dereference via daemon/images/image_history.go.
CVSS Score
6.5
EPSS Score
0.003
Published
2024-11-29
moby v25.0.5 is affected by a Race Condition in builder/builder-next/adapters/snapshot/layer.go. The vulnerability could be used to trigger concurrent builds that call the EnsureLayer function resulting in resource leaks/exhaustion.
CVSS Score
6.5
EPSS Score
0.002
Published
2024-11-29
Moby is an open source container framework that is a key component of Docker Engine, Docker Desktop, and other distributions of container tooling or runtimes. In 26.0.0, IPv6 is not disabled on network interfaces, including those belonging to networks where `--ipv6=false`. An container with an `ipvlan` or `macvlan` interface will normally be configured to share an external network link with the host machine. Because of this direct access, (1) Containers may be able to communicate with other hosts on the local network over link-local IPv6 addresses, (2) if router advertisements are being broadcast over the local network, containers may get SLAAC-assigned addresses, and (3) the interface will be a member of IPv6 multicast groups. This means interfaces in IPv4-only networks present an unexpectedly and unnecessarily increased attack surface. The issue is patched in 26.0.2. To completely disable IPv6 in a container, use `--sysctl=net.ipv6.conf.all.disable_ipv6=1` in the `docker create` or `docker run` command. Or, in the service configuration of a `compose` file.
CVSS Score
4.7
EPSS Score
0.001
Published
2024-04-18
Moby is an open source container framework that is a key component of Docker Engine, Docker Desktop, and other distributions of container tooling or runtimes. Moby's networking implementation allows for many networks, each with their own IP address range and gateway, to be defined. This feature is frequently referred to as custom networks, as each network can have a different driver, set of parameters and thus behaviors. When creating a network, the `--internal` flag is used to designate a network as _internal_. The `internal` attribute in a docker-compose.yml file may also be used to mark a network _internal_, and other API clients may specify the `internal` parameter as well.
When containers with networking are created, they are assigned unique network interfaces and IP addresses. The host serves as a router for non-internal networks, with a gateway IP that provides SNAT/DNAT to/from container IPs.
Containers on an internal network may communicate between each other, but are precluded from communicating with any networks the host has access to (LAN or WAN) as no default route is configured, and firewall rules are set up to drop all outgoing traffic. Communication with the gateway IP address (and thus appropriately configured host services) is possible, and the host may communicate with any container IP directly.
In addition to configuring the Linux kernel's various networking features to enable container networking, `dockerd` directly provides some services to container networks. Principal among these is serving as a resolver, enabling service discovery, and resolution of names from an upstream resolver.
When a DNS request for a name that does not correspond to a container is received, the request is forwarded to the configured upstream resolver. This request is made from the container's network namespace: the level of access and routing of traffic is the same as if the request was made by the container itself.
As a consequence of this design, containers solely attached to an internal network will be unable to resolve names using the upstream resolver, as the container itself is unable to communicate with that nameserver. Only the names of containers also attached to the internal network are able to be resolved.
Many systems run a local forwarding DNS resolver. As the host and any containers have separate loopback devices, a consequence of the design described above is that containers are unable to resolve names from the host's configured resolver, as they cannot reach these addresses on the host loopback device. To bridge this gap, and to allow containers to properly resolve names even when a local forwarding resolver is used on a loopback address, `dockerd` detects this scenario and instead forward DNS requests from the host namework namespace. The loopback resolver then forwards the requests to its configured upstream resolvers, as expected.
Because `dockerd` forwards DNS requests to the host loopback device, bypassing the container network namespace's normal routing semantics entirely, internal networks can unexpectedly forward DNS requests to an external nameserver. By registering a domain for which they control the authoritative nameservers, an attacker could arrange for a compromised container to exfiltrate data by encoding it in DNS queries that will eventually be answered by their nameservers.
Docker Desktop is not affected, as Docker Desktop always runs an internal resolver on a RFC 1918 address.
Moby releases 26.0.0, 25.0.4, and 23.0.11 are patched to prevent forwarding any DNS requests from internal networks. As a workaround, run containers intended to be solely attached to internal networks with a custom upstream address, which will force all upstream DNS queries to be resolved from the container's network namespace.
CVSS Score
5.9
EPSS Score
0.002
Published
2024-03-20
Moby is an open-source project created by Docker to enable software containerization. The classic builder cache system is prone to cache poisoning if the image is built FROM scratch. Also, changes to some instructions (most important being HEALTHCHECK and ONBUILD) would not cause a cache miss. An attacker with the knowledge of the Dockerfile someone is using could poison their cache by making them pull a specially crafted image that would be considered as a valid cache candidate for some build steps. 23.0+ users are only affected if they explicitly opted out of Buildkit (DOCKER_BUILDKIT=0 environment variable) or are using the /build API endpoint. All users on versions older than 23.0 could be impacted. Image build API endpoint (/build) and ImageBuild function from github.com/docker/docker/client is also affected as it the uses classic builder by default. Patches are included in 24.0.9 and 25.0.2 releases.
CVSS Score
6.9
EPSS Score
0.001
Published
2024-02-01
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Two malicious build steps running in parallel sharing the same cache mounts with subpaths could cause a race condition that can lead to files from the host system being accessible to the build container. The issue has been fixed in v0.12.5. Workarounds include, avoiding using BuildKit frontend from an untrusted source or building an untrusted Dockerfile containing cache mounts with --mount=type=cache,source=... options.
CVSS Score
8.7
EPSS Score
0.005
Published
2024-01-31
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. A malicious BuildKit frontend or Dockerfile using RUN --mount could trick the feature that removes empty files created for the mountpoints into removing a file outside the container, from the host system. The issue has been fixed in v0.12.5. Workarounds include avoiding using BuildKit frontends from an untrusted source or building an untrusted Dockerfile containing RUN --mount feature.
CVSS Score
10.0
EPSS Score
0.038
Published
2024-01-31
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