CVE-2026-85063 node-csv: Prototype replacement still reachable via columns path
Attackers can exploit prototype pollution in node-csv to inject malicious data and potentially execute code when specific parsing options are enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-85063?
CVE-2026-85063 is a medium-severity code injection vulnerability in adaltas node-csv, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
node-csv is a full-featured CSV parser with a simple API that is tested against large datasets. Prior to 7.0.2, csv-parse with the columns and group_columns_by_name options enabled treats a duplicate __proto__ header as an existing property in packages/csv-parse/lib/api/index.js, assigns an attacker-controlled array through obj['__proto__'], and replaces the parsed record object's prototype. A malicious CSV header can therefore inject inherited array values into the returned record, hide those inherited values from JSON serialization, and affect property enumeration and type or shape checks in applications that process the record. This issue is fixed in version 7.0.2.
Weakness: CWE-1321
Which versions are affected by CVE-2026-85063?
2 open source packages ship an affected version, including csv-parse.
| Package | Affected | Fixed in |
|---|---|---|
csv-parse npm | All versions | 7.0.2 |
csv-parse npm | All versions | 7.0.2 |
How do I fix CVE-2026-85063?
Upgrade csv-parse to 7.0.2 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-85063 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85063 exists.
Sources
Also known as CLEANSTART-2026-LJ34730, CLEANSTART-2026-OY61738, CLEANSTART-2026-WQ57652, DEBIAN-CVE-2026-85063, ECHO-2240-6ce7-c82e, GHSA-8cw4-87c7-c6xx and 4 more.