Summary
Apollo Router Coprocessors may cause Denial-of-Service when handling request bodies
When using External Coprocessing:
Instances of the Apollo Router running versions >=1.21.0 and <1.52.1 are impacted by a denial-of-service vulnerability if all of the following are true:
- Router has been configured to support External Coprocessing.
- Router has been configured to send request bodies to coprocessors. This is a non-default configuration and must be configured intentionally by administrators.
You can identify if you are impacted by reviewing your router's configuration YAML for the following config:
...
coprocessor:
url: http://localhost:9000 # likely different in your environment
router:
request:
body: true # this must be set to 'true' to be impacted
...
External Coprocessing was initially made available as an experimental feature with Router version 1.21.0 on 2023-06-20 and was made generally available with Router version 1.38.0 on 2024-01-19. More information about the Router’s External Coprocessing feature is available here.
When using Native Rust Plugins:
Instances of the Apollo Router running versions >=1.7.0 and <1.52.1 are impacted by a denial-of-service vulnerability if all of the following are true:
- Router has been configured to use a custom-developed Native Rust Plugin
- The plugin accesses
Request.router_requestin theRouterServicelayer - You are accumulating the body from
Request.router_requestinto memory
To use a plugin, you need to be running a customized Router binary. Additionally, you need to have a plugins section with at least one plugin defined in your Router’s configuration YAML. That plugin would also need to define a custom router_service method.
You can check for a defined plugin by reviewing for the following in your Router’s configuration YAML:
...
plugins:
custom_plugin_name:
# custom config here
...
You can check for a custom router_service method in a plugin, by reviewing for the following function signature in your plugin’s source:
fn router_service(&self, service: router::BoxService) -> router::BoxService
More information about the Router’s Native Rust Plugin feature is available here.
Impact Detail
If using an impacted configuration, the Router will load entire HTTP request bodies into memory without respect to other HTTP request size-limiting configurations like limits.http_max_request_bytes. This can cause the Router to be out-of-memory (OOM) terminated if a sufficiently large request is sent to the Router.
By default, the Router sets limits.http_max_request_bytes to 2 MB. More information about the Router’s request limiting features is available here.
Workarounds
If you cannot upgrade, you can mitigate the denial-of-service opportunity impacting External Coprocessors by setting the coprocessor.router.request.body configuration option to false. Please note that changing this configuration option will change the information sent to any coprocessors you have configured and may impact functionality implemented by those coprocessors.
If you have developed a Native Rust Plugin and cannot upgrade, you can update your plugin to either not accumulate the request body or enforce a maximum body size limit.
You can also mitigate this issue by limiting HTTP body payload sizes prior to the Router (e.g., in a proxy or web application firewall appliance).
References
Apollo Router 1.52.1 Release Notes
External Coprocessing documentation
HTTP Request Limiting documentation
Native Rust Plugin documentation
Impact
Instances of the Apollo Router using either of the following may be impacted by a denial-of-service vulnerability.
- External Coprocessing with specific configurations; or
- Native Rust Plugins accessing the Router request body in the RouterService layer
Router customizations using Rhai scripts are not impacted.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
CVE-2024-43783 has a CVSS score of 7.5 (High). The vector is network-reachable, no 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 (1.52.1); 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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If you have an impacted configuration as defined above, please upgrade to at least Apollo Router 1.52.1.
Frequently Asked Questions
- What is CVE-2024-43783? CVE-2024-43783 is a high-severity allocation of resources without limits or throttling vulnerability in apollo-router (rust), affecting versions >= 1.7.0, < 1.52.1. It is fixed in 1.52.1. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- How severe is CVE-2024-43783? CVE-2024-43783 has a CVSS score of 7.5 (High). 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 apollo-router are affected by CVE-2024-43783? apollo-router (rust) versions >= 1.7.0, < 1.52.1 is affected.
- Is there a fix for CVE-2024-43783? Yes. CVE-2024-43783 is fixed in 1.52.1. Upgrade to this version or later.
- Is CVE-2024-43783 exploitable, and should I be worried? Whether CVE-2024-43783 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-2024-43783 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-2024-43783? Upgrade
apollo-routerto 1.52.1 or later.