CVE-2026-21852
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Claude Code Leaks Data via Malicious Environment Configuration Before Trust Confirmation
rank 40 = 19 + 19 + 0 + 2 + 0
rank@v1 · scheduled
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.26304 · without this subject the record ranks 21
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 7.5, from NVD · without this subject the record ranks 21
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 40
How much of the world it touches
NVD CPE configurations
1 product in the CPE ranges · without this subject the record ranks 38
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 40
$754,000 = $4.99M incident cost x 0.5743756121449558 exposure x 0.26304 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
This record is one instance of CWE-522, insufficiently protected credentials. The index holds 1501 prior instances of this class, 5 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
Sources disagree here.
Both shown, dated. We don't pick winners. disagreement-rules@v1
Running anthropics claude-code? Check your version
A deterministic range check against the ranges this record publishes. It tells you where a version sits in the record, not whether your deployment is exploitable. No account needed.
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Harm, if it fires from the vector and the weakness
Written for the ticket you're about to file.
CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Proof-of-concept published · 1 public repository, 2026-02-27.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published · 1 public repository2026-02-27receipt
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
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. receipt
Read the rest of the CNA's description
Users performing manual updates are advised to update to version 2.0.65, which contains a patch, or to the latest version.
NVD's analysis a second authority
- severity
- 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- weakness
- CWE-522
- affected versions
- anthropic claude code < 2.0.65
- also scored by
- [email protected] 5.3 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
The CNA scored it 5.3 and NVD 7.5. Both are shown because both were published; we do not pick one.
check it yourself github.com receipt
Dated events
Movement the material steps
Show all 18 observations
18 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The pattern, elsewhere
This record is one instance of CWE-522, insufficiently protected credentials. The index holds 1501 prior instances of this class, 5 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
1501 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
Siblings and hubs
Records related to this one
None. No alias set, and nothing in the corpus cites this identifier or shares its product family within 60 days.
Browse the index from here
These are index-wide views, not findings about CVE-2026-21852.
What usually comes next
Everything above needs no account. What is below is work: assembling it, scoping it to your estate, watching it, and handing it to someone else.