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01 Record

CVE-2026-21852

Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation

MediumPUBLISHEDCNA: GitHub_M
CNA base score5.3 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

02 Description

Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
27.50% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 98.0% of scored records. A rank, not a probability.
NVD base score
5.3 (CVSS v4.0), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD analysis status
Analyzed. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-01-21 20:42Z9 MO AGO
Last updated
2026-01-21 21:34Z9 MO AGO
Reserved
2026-01-05
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Medium (CVSS 5.3)
CNA CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
Weaknesses
  • CWE-522Insufficiently Protected CredentialsClass
Data version
5.2
Document digest
62a3ed8ff2d6395c88e24dc8ec873c584994d495ad86908174c60fbb6e429bef

05 Affected products

VendorProductVersionsPlatforms
anthropicsclaude-code< 2.0.65—

06 References