Stacklok Minder vulnerable to denial of service from maliciously crafted templatesGHSA-crgc-2583-rw27
MEDIUMFix: stacklok/minder@fe321d3GHSA-crgc-2583-rw27 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in github.com/stacklok/minder. A fix is available for github.com/stacklok/minder — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-crgc-2583-rw27.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/stacklok/minderReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Minder engine is susceptible to a denial of service from memory exhaustion that can be triggered from maliciously created templates.
Minder engine uses templating to generate strings for various use cases such as URLs, messages for pull requests, descriptions for advisories. In some cases can the user control both the template and the params for it, and in a subset of these cases, Minder reads the generated template entirely into memory. When Minders templating meets both of these conditions, an attacker is able to generate large enough templates that Minder will exhaust memory and crash.
One of these places is the REST ingester:
With control over both endpoint and retp on the following line:
… an attacker can make Minder generate a large template that Minder reads into memory on the following line by invoking endpoint.String():
Consider this example:
package main
import (
"fmt"
"html/template"
"os"
)
type EndpointTemplateParams struct {
// Params are the parameters to be used in the template
Params map[string]any
}
func main() {
retp := &EndpointTemplateParams{
Params: map[string]any{
"params": make([]string, 10),
},
}
fmt.Println(retp)
const templ = `
{{range $idx, $e := .Params.params}}
loooooooooooooooooooooooooooooooong-string-{{$idx}}
{{end}}
{{range $idx, $e := .Params.params}}
loooooooooooooooooooooooooooooooong-string-{{$idx}}
{{end}}
{{range $idx, $e := .Params.params}}
loooooooooooooooooooooooooooooooong-string-{{$idx}}
{{end}}`
tmpl := template.Must(template.New("").Parse(templ))
if err := tmpl.Execute(os.Stdout, retp); err != nil {
panic(err)
}
}
This example imitates the behavior on these lines:
Running this example generates the following template:
loooooooooooooooooooooooooooooooong-string-0
loooooooooooooooooooooooooooooooong-string-1
loooooooooooooooooooooooooooooooong-string-2
loooooooooooooooooooooooooooooooong-string-3
loooooooooooooooooooooooooooooooong-string-4
loooooooooooooooooooooooooooooooong-string-5
loooooooooooooooooooooooooooooooong-string-6
loooooooooooooooooooooooooooooooong-string-7
loooooooooooooooooooooooooooooooong-string-8
loooooooooooooooooooooooooooooooong-string-9
loooooooooooooooooooooooooooooooong-string-0
loooooooooooooooooooooooooooooooong-string-1
loooooooooooooooooooooooooooooooong-string-2
loooooooooooooooooooooooooooooooong-string-3
loooooooooooooooooooooooooooooooong-string-4
loooooooooooooooooooooooooooooooong-string-5
loooooooooooooooooooooooooooooooong-string-6
loooooooooooooooooooooooooooooooong-string-7
loooooooooooooooooooooooooooooooong-string-8
loooooooooooooooooooooooooooooooong-string-9
loooooooooooooooooooooooooooooooong-string-0
loooooooooooooooooooooooooooooooong-string-1
loooooooooooooooooooooooooooooooong-string-2
loooooooooooooooooooooooooooooooong-string-3
loooooooooooooooooooooooooooooooong-string-4
loooooooooooooooooooooooooooooooong-string-5
loooooooooooooooooooooooooooooooong-string-6
loooooooooooooooooooooooooooooooong-string-7
loooooooooooooooooooooooooooooooong-string-8
loooooooooooooooooooooooooooooooong-string-9
A malicious user can call the loop more times, increase the loop count and/or make the repeated long string longer to make the size of the template bigger.
A sufficiently large template will consume a lot of memory on this line which will exhaust memory on the machine and crash the Minder server:
Minder should enforce a limit to generated templates before reading them into memory.
The following templates are believed to be vulnerable:
Minder has a few other templates especially in its engine which needs reviewing too. As a default, all templates should be limited in size before Minder reads them into memory.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/stacklok/minder | all versions | 0.0.50go get github.com/stacklok/minder@v0.0.50 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/stacklok/minder, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/stacklok/minder to 0.0.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-crgc-2583-rw27 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is GHSA-crgc-2583-rw27 in your dependencies?
Find it across Go, including transitive dependencies.