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No exploitation reportedFix available

CVE-2023-28840

No exploitation reported by the sources we read.

  • Published2023-04-04
  • Fixed in23.0.3 · 23.0.3+incompatible · 20.10.24 · 20.10.24+incompatible
  • WeaknessCWE-203 · CWE-420 · CWE-636

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Moby is an open source container framework developed by Docker Inc. that is distributed as Docker, Mirantis Container Runtime, and various other downstream projects/products. The Moby daemon component (`dockerd`), which is developed as moby/moby, is commonly referred to as *Docker*. Swarm Mode, which is compiled in and delivered by default in dockerd and is thus present in most major Moby downstreams, is a simple, built-in container orchestrator that is implemented through a combination of SwarmKit and supporting network code. The overlay network driver is a core feature of Swarm Mode, providing isolated virtual LANs that allow communication between containers and services across the cluster. This driver is an implementation/user of VXLAN, which encapsulates link-layer (Ethernet) frames in UDP datagrams that tag the frame with a VXLAN Network ID (VNI) that identifies the originating overlay network. In addition, the overlay network driver supports an optional, off-by-default encrypted mode, which is especially useful when VXLAN packets traverses an untrusted network between nodes. Encrypted overlay networks function by encapsulating the VXLAN datagrams through the use of the IPsec Encapsulating Security Payload protocol in Transport mode. By deploying IPSec encapsulation, encrypted overlay networks gain the additional properties of source authentication through cryptographic proof, data integrity through check-summing, and confidentiality through encryption. When setting an endpoint up on an encrypted overlay network, Moby installs three iptables (Linux kernel firewall) rules that enforce both incoming and outgoing IPSec. These rules rely on the u32 iptables extension provided by the xt_u32 kernel module to directly filter on a VXLAN packet's VNI field, so that IPSec guarantees can be enforced on encrypted overlay networks without interfering with other overlay networks or other users of VXLAN. Two iptables rules serve to filter incoming VXLAN datagrams with a VNI that corresponds to an encrypted network and discards unencrypted datagrams. The rules are appended to the end of the INPUT filter chain, following any rules that have been previously set by the system administrator. Administrator-set rules take precedence over the rules Moby sets to discard unencrypted VXLAN datagrams, which can potentially admit unencrypted datagrams that should have been discarded. The injection of arbitrary Ethernet frames can enable a Denial of Service attack. A sophisticated attacker may be able to establish a UDP or TCP connection by way of the container’s outbound gateway that would otherwise be blocked by a stateful firewall, or carry out other escalations beyond simple injection by smuggling packets into the overlay network. Patches are available in Moby releases 23.0.3 and 20.10.24. As Mirantis Container Runtime's 20.10 releases are numbered differently, users of that platform should update to 20.10.16. Some workarounds are available. Close the VXLAN port (by default, UDP port 4789) to incoming traffic at the Internet boundary to prevent all VXLAN packet injection, and/or ensure that the `xt_u32` kernel module is available on all nodes of the Swarm cluster.

Timeline

dates in UTC
  1. 2023-04-0422:15CVE publishedNVD

Versions per branch

NVD · OSV
Mobyproject moby
BranchAffectedFixed in
23.0≥ 23.0.0, < 23.0.323.0.3
23.0≥ 23.0.0+incompatible, < 23.0.3+incompatible23.0.3+incompatible
20.10≥ 1.12.0, < 20.10.2420.10.24
20.10≥ 1.12.0, < 20.10.24+incompatible20.10.24+incompatible

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • moby
    Affected
    • = >= 1.12.0, < 20.10.24no fix stated
    • = >= 23.0.0, < 23.0.3no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2023-04-04

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • apkoWolfiall versions · fixed in 0.7.3-r1
  • apkoChainguardall versions · fixed in 0.7.3-r1
  • bomWolfiall versions · fixed in 0.6.0-r0
  • bomChainguardall versions · fixed in 0.6.0-r0
  • ctopWolfiall versions · fixed in 0.7.7-r13
  • ctopChainguardall versions · fixed in 0.7.7-r13
  • dockerSUSE:Linux Enterprise Server for SAP Applications 15 SP3all versions · fixed in 24.0.5_ce-150000.185.1
  • dockerSUSE:Linux Enterprise Server for SAP Applications 15 SP2all versions · fixed in 24.0.5_ce-150000.185.1

77 more package ranges on OSV.dev

Vendor advisories

  • CVE-2023-28840 Red Hat Product Security164 products fixed

    moby: Encrypted overlay network may be unauthenticated

  • RHBA-2024:1246 Red Hat Product Security164 products fixed

    Red Hat Bug Fix Advisory: Multicluster Engine for Kubernetes 2.4.4 bug fixes

Full record on NVD

Fix

  1. Update Mobyproject moby to 23.0.3 · 23.0.3+incompatible · 20.10.24 · 20.10.24+incompatible
  2. Vendor fix Red Hat Product Security RHBA-2024:1246 · 164 productsFor multicluster engine for Kubernetes, see the following documentation for details on how to install the images: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.9/html/clusters/cluster_mce_overview#installing-while-connected-online-mce

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2025-02-10
  • CNACVSS 3.17.5known since 2026-10-23
  • NVDCVSS 3.18.7read 2026-10-23
  • CNAweakness (CWE)CWE-420, CWE-636known since 2026-10-23
  • NVDweakness (CWE)CWE-203, CWE-755read 2026-10-23
  • FIRST EPSSEPSS score2.6 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2023-04-04

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H
Published
2023-04-04
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-232p-vwff-86mp

Frequently asked questions

What is CVE-2023-28840?

Moby is an open source container framework developed by Docker Inc. that is distributed as Docker, Mirantis Container Runtime, and various other downstream projects/products. The Moby daemon component (`dockerd`), which is developed as moby/moby, is commonly referred to as *Docker*. Swarm Mode, which is compiled in and delivered by default in dockerd and is thus present in most major Moby downstreams, is a simple, built-in container orchestrator that is implemented through a combination of SwarmKit and supporting network code. The overlay network driver is a core feature of Swarm Mode, providing isolated virtual LANs that allow communication between containers and services across the cluster. This driver is an implementation/user of VXLAN, which encapsulates link-layer (Ethernet) frames in UDP datagrams that tag the frame with a VXLAN Network ID (VNI) that identifies the originating overlay network. In addition, the overlay network driver supports an optional, off-by-default encrypted mode, which is especially useful when VXLAN packets traverses an untrusted network between nodes. Encrypted overlay networks function by encapsulating the VXLAN datagrams through the use of the IPsec Encapsulating Security Payload protocol in Transport mode. By deploying IPSec encapsulation, encrypted overlay networks gain the additional properties of source authentication through cryptographic proof, data integrity through check-summing, and confidentiality through encryption. When setting an endpoint up on an encrypted overlay network, Moby installs three iptables (Linux kernel firewall) rules that enforce both incoming and outgoing IPSec. These rules rely on the u32 iptables extension provided by the xt_u32 kernel module to directly filter on a VXLAN packet's VNI field, so that IPSec guarantees can be enforced on encrypted overlay networks without interfering with other overlay networks or other users of VXLAN. Two iptables rules serve to filter incoming VXLAN datagrams with a VNI that corresponds to an encrypted network and discards unencrypted datagrams. The rules are appended to the end of the INPUT filter chain, following any rules that have been previously set by the system administrator. Administrator-set rules take precedence over the rules Moby sets to discard unencrypted VXLAN datagrams, which can potentially admit unencrypted datagrams that should have been discarded. The injection of arbitrary Ethernet frames can enable a Denial of Service attack. A sophisticated attacker may be able to establish a UDP or TCP connection by way of the container’s outbound gateway that would otherwise be blocked by a stateful firewall, or carry out other escalations beyond simple injection by smuggling packets into the overlay network. Patches are available in Moby releases 23.0.3 and 20.10.24. As Mirantis Container Runtime's 20.10 releases are numbered differently, users of that platform should update to 20.10.16. Some workarounds are available. Close the VXLAN port (by default, UDP port 4789) to incoming traffic at the Internet boundary to prevent all VXLAN packet injection, and/or ensure that the `xt_u32` kernel module is available on all nodes of the Swarm cluster.

Is CVE-2023-28840 actively exploited?

Active exploitation of CVE-2023-28840 has not been confirmed. Its EPSS score was 2.6% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-28840?

CVE-2023-28840 has a CVSS v3 base score of 8.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H.

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