Is CVE-2026-21852 in the CISA KEV catalog?

No. CVE-2026-21852 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-21852?

CVE-2026-21852 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-21852?

CVE-2026-21852 has an EPSS score of 22.97% (98th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-21852?

Upgrade claude code to 2.0.65 or later.

CVE & CISA-KEV Catalog

CVE-2026-21852

HIGHEPSS 98th pctl

7.5

CVSS v3

NVD

Description

Claude Code is an agentic coding tool. Prior to version 2.0.65, vulnerability in Claude Code's project-load flow allowed malicious repositories to exfiltrate data including Anthropic API keys before users confirmed trust. An attacker-controlled repository could include a settings file that sets ANTHROPIC_BASE_URL to an attacker-controlled endpoint and when the repository was opened, Claude Code would read the configuration and immediately issue API requests before showing the trust prompt, potentially leaking the user's API keys. Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to version 2.0.65, which contains a patch, or to the latest version.

CWE-522

How to fix

Remediation Available

claude codeNVD

Affected:< 2.0.65Fixed in:2.0.65CVE-2026-21852derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

22.97%probability of exploitation in 30 days

98thpercentile

Very high risk: more likely to be exploited than 98% of all known CVEs.

References

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-522 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-17662	Critical	9.8	97%	-	-
CVE-2020-29583	Critical	9.8	90%	KEV	-
CVE-2021-30116	Critical	10.0	86%	KEV + Ransom	Fix
CVE-2024-44000	Critical	9.8	83%	-	Fix
CVE-2018-9160	Critical	9.8	77%	-	-
CVE-2017-9248	Critical	9.8	75%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-02.