CVE-2021-41248

CVE-2021-41248 is a high-severity vulnerability in Graphql Graphiql with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Description

GraphiQL is the reference implementation of this monorepo, GraphQL IDE, an official project under the GraphQL Foundation. All versions of graphiql older than [email protected] are vulnerable to compromised HTTP schema introspection responses or schema prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete. In order for the attack to take place, the user must load a vulnerable schema in graphiql. There are a number of ways that can occur. By default, the schema URL is not attacker-controllable in graphiql or in its suggested implementations or examples, leaving only very complex attack vectors. If a custom implementation of graphiql's fetcher allows the schema URL to be set dynamically, such as a URL query parameter like ?endpoint= in graphql-playground, or a database provided value, then this custom graphiql implementation is vulnerable to phishing attacks, and thus much more readily available, low or no privelege level xss attacks. The URLs could look like any generic looking graphql schema URL. It should be noted that desktop clients such as Altair, Insomnia, Postwoman, do not appear to be impacted by this. This vulnerability does not impact codemirror-graphql, monaco-graphql or other dependents, as it exists in onHasCompletion.ts in graphiql. It does impact all forks of graphiql, and every released version of graphiql.

Frequently asked questions

What is CVE-2021-41248?
GraphiQL is the reference implementation of this monorepo, GraphQL IDE, an official project under the GraphQL Foundation. All versions of graphiql older than [email protected] are vulnerable to compromised HTTP schema introspection responses or schema prop values with malicious GraphQL type names, exposing a dynamic XSS attack surface that can allow code injection on operation autocomplete. In order for the attack to take place, the user must load a vulnerable schema in graphiql. There are a number of ways that can occur. By default, the schema URL is not attacker-controllable in graphiql or in its suggested implementations or examples, leaving only very complex attack vectors. If a custom implementation of graphiql's fetcher allows the schema URL to be set dynamically, such as a URL query parameter like ?endpoint= in graphql-playground, or a database provided value, then this custom graphiql implementation is vulnerable to phishing attacks, and thus much more readily available, low or no privelege level xss attacks. The URLs could look like any generic looking graphql schema URL. It should be noted that desktop clients such as Altair, Insomnia, Postwoman, do not appear to be impacted by this. This vulnerability does not impact codemirror-graphql, monaco-graphql or other dependents, as it exists in onHasCompletion.ts in graphiql. It does impact all forks of graphiql, and every released version of graphiql.
How severe is CVE-2021-41248?
CVE-2021-41248 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2021-41248 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41248?
CVE-2021-41248 affects Graphql Graphiql. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41248?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41248 published?
CVE-2021-41248 was published on 2021-11-04 and last updated on 2026-06-17.

References

Affected products (1)

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