CVE-2026-103921: Cert Validation Flaw (CVSS 7.4)

Description

GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 1.1.35, the executor-legacy-ws buildWSLegacyExecutor() function hardcodes TLS certificate rejection off for Node.js connections to wss:// endpoints. Applications using the executor directly, or url-loader with SubscriptionProtocol.LEGACY_WS, can therefore accept an attacker-controlled certificate when a network-positioned attacker intercepts the connection. Authentication material in connectionParams or headers can be disclosed, and subscription data can be modified. Browser WebSocket clients are unaffected because browsers enforce certificate validation. This issue is fixed in version 1.1.35.

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CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

References

Other References

https://github.com/ardatan/graphql-tools/commit/3831a0661514c91d99971052f983552556880402 https://github.com/ardatan/graphql-tools/pull/8426 https://github.com/ardatan/graphql-tools/releases/tag/@graphql-tools/[email protected] https://github.com/ardatan/graphql-tools/security/advisories/GHSA-6fw5-9hq8-w87g

Frequently Asked Questions

What is CVE-2026-103921? +

GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 1.1.35, the executor-legacy-ws buildWSLegacyExecutor() function hardcodes TLS certificate rejection off for Node.js connections to wss:// endpoints. Applications using the executor directly, or url-loader with SubscriptionProtocol.LEGACY_WS, can therefore accept an attacker-controlled certificate when a network-positioned attacker intercepts the connection. Authentication material in connectionParams or headers can be disclosed, and subscription data can be modified. Browser WebSocket clients are unaffected because browsers enforce certificate validation. This issue is fixed in version 1.1.35. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-103921? +

CVE-2026-103921 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-103921? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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