CVE-2021-41249 [High] | XSS in Playground

GraphQL Playground is a GraphQL IDE for development of graphQL focused applications. All versions of graphql-playground-react 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 malicious schema in graphql-playground. There are several ways this can occur, including by specifying the URL to a malicious schema in the endpoint query parameter. If a user clicks on a link to a GraphQL Playground installation that specifies a malicious server, arbitrary JavaScript can run in the user's browser, which can be used to exfiltrate user credentials or other harmful goals. If you are using graphql-playground-react directly in your client app, upgrade to version 1.7.28 or later.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-04	0.52%	0.36%	-0.15%
2	2026-03-01	0.36%	0.52%	+0.15%
3	2026-02-14	—	0.36%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-04

0.52%

0.36%

-0.15%

2026-03-01

0.36%

0.52%

+0.15%

2026-02-14

—

0.36%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.1	3.1	HIGH	`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	1.6	5.5	[email protected]
4.7	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	1.6	2.7	[email protected]
2.6	2.0	LOW	`AV:N/AC:H/Au:N/C:N/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:H) Exploitation requires uncommon or highly specific conditions. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	4.9	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.1

3.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:L): Might cause slowdowns, glitches, or partial disruption—not a full brick.

1.6

5.5

[email protected]

4.7

3.1

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

1.6

2.7

[email protected]

2.6

2.0

LOW

AV:N/AC:H/Au:N/C:N/I:P/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:H): Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:N): No availability impact.

4.9

2.9

[email protected]

Affected software / configurations for CVE-2021-41249

Vendor	Product	Version	Raw CPE
graphql	playground	< 1.7.28	cpe:2.3:a:graphql:playground::::::node.js::*

References for CVE-2021-41249

URL	Tags
https://github.com/graphql/graphiql/security/advisories/GHSA-x4r7-m2q9-69c8	Not Applicable Third Party Advisory
https://github.com/graphql/graphql-playground/commit/b8a956006835992f12c46b90384a79ab82bcadad	Patch Third Party Advisory
https://github.com/graphql/graphql-playground/security/advisories/GHSA-59r9-6jp6-jcm7	Third Party Advisory

URL

CVE-2021-41249 | XSS vulnerability in GraphQL Playground

Exploit prediction scoring system (EPSS) score for CVE-2021-41249

Common vulnerability scoring system (CVSS) metrics for CVE-2021-41249

Weakness enumeration for CVE-2021-41249

GitHub Security Advisory for CVE-2021-41249

Affected software / configurations for CVE-2021-41249

References for CVE-2021-41249