Summary
KubeEdge: Unbounded allocation in viaduct packer enables authenticated remote DoS against CloudHub
KubeEdge CloudHub uses the viaduct packer to decode messages received from connected peers. The packer reads a 32-bit payload length from the message header and previously allocated a buffer of that size without enforcing an upper bound.
An authenticated peer that can establish a viaduct connection to CloudHub can send a crafted message header containing an excessively large payload length. This may cause CloudHub to allocate a large amount of memory and can result in memory exhaustion, process termination, or denial of service.
Root cause
The viaduct packer trusted the payload length encoded in the message header and allocated the payload buffer before validating whether the declared length was within an acceptable range.
Workarounds
Before patched versions are available, operators should:
- Restrict access to the CloudHub endpoint to trusted edge nodes and networks
- Protect and rotate edge-node credentials
- Revoke credentials belonging to decommissioned or potentially compromised nodes
- Apply memory limits and restart policies to the CloudHub workload
- Monitor CloudHub memory consumption and unexpected connection activity
Affected component
pkg/viaduct/pkg/packer- CloudHub viaduct message-processing path
Credits
KubeEdge thanks Sang-Hoon Choi (KoreaSecurity, Sejong University)
for responsibly reporting this issue and for coordinating with the KubeEdge
maintainers through the security disclosure process.
Impact
A successfully authenticated malicious or compromised edge node may repeatedly send crafted viaduct message headers to increase CloudHub memory consumption.
Depending on available memory and deployment limits, exploitation may cause:
- Increased CloudHub memory usage
- Out-of-memory termination
- CloudHub restart loops
- Temporary disruption of cloud-edge communication
Authentication to the viaduct endpoint is required. This issue does not provide unauthenticated access or direct code execution.
CVE-2026-62370 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.21.2, 1.22.2, 1.23.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The fix introduces a maximum viaduct payload size of 32 MiB.
The updated implementation:
- Rejects oversized payload lengths in the reader before memory allocation
- Enforces the same maximum size in the writer
- Adds regression tests covering oversized and valid payloads
Fixes have been prepared for the following patch releases:
- KubeEdge v1.23.1
- KubeEdge v1.22.2
- KubeEdge v1.21.2
These versions should not be listed as released until the coordinated release process is complete.
Frequently Asked Questions
- What is CVE-2026-62370? CVE-2026-62370 is a medium-severity security vulnerability in github.com/kubeedge/kubeedge (go), affecting versions >= 1.0.0, < 1.21.2. It is fixed in 1.21.2, 1.22.2, 1.23.1.
- How severe is CVE-2026-62370? CVE-2026-62370 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/kubeedge/kubeedge are affected by CVE-2026-62370? github.com/kubeedge/kubeedge (go) versions >= 1.0.0, < 1.21.2 is affected.
- Is there a fix for CVE-2026-62370? Yes. CVE-2026-62370 is fixed in 1.21.2, 1.22.2, 1.23.1. Upgrade to this version or later.
- Is CVE-2026-62370 exploitable, and should I be worried? Whether CVE-2026-62370 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-62370 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-62370?
- Upgrade
github.com/kubeedge/kubeedgeto 1.21.2 or later - Upgrade
github.com/kubeedge/kubeedgeto 1.22.2 or later - Upgrade
github.com/kubeedge/kubeedgeto 1.23.1 or later
- Upgrade