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HIGH

CVE-2026-84961

CVSS v3

7.4

HIGH

EPSS Score

0.2 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still p

Technical details

Published
2026-09-04
Last Modified
2026-09-04

Frequently asked questions

What is CVE-2026-84961?

undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still p

Is CVE-2026-84961 actively exploited?

Active exploitation of CVE-2026-84961 has not been confirmed. Its EPSS score was 0.2% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-84961?

CVE-2026-84961 has a CVSS v3 base score of 7.4 (HIGH severity).

Is CVE-2026-84961 affecting your environment?

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