HOME VULNERABILITIESCVE-2020-26256

MEDIUM

CVE-2020-26256

CWE-400Published: December 8, 2020· Updated: Jun 17, 2026

6.5

CVSS v3.1

Official Description

Fast-csv is an npm package for parsing and formatting CSVs or any other delimited value file in node. In fast-cvs before version 4.3.6 there is a possible ReDoS vulnerability (Regular Expression Denial of Service) when using ignoreEmpty option when parsing. This has been patched in `v4.3.6` You will only be affected by this if you use the `ignoreEmpty` parsing option. If you do use this option it is recommended that you upgrade to the latest version `v4.3.6` This vulnerability was found using a CodeQL query which identified `EMPTY_ROW_REGEXP` regular expression as vulnerable.

Technical Analysis

CVE-2020-26256 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.Low

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Affected Vendors & Products

c2fo1 product(s)

fast-csv

Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829e

PATCHhttps://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829e

ADVISORYhttps://github.com/C2FO/fast-csv/issues/540

ADVISORYhttps://github.com/C2FO/fast-csv/security/advisories/GHSA-8cv5-p934-3hwp

ADVISORYhttps://lgtm.com/query/8609731774537641779/

ADVISORYhttps://www.npmjs.com/package/fast-csv

ADVISORYhttps://github.com/C2FO/fast-csv/issues/540

ADVISORYhttps://github.com/C2FO/fast-csv/security/advisories/GHSA-8cv5-p934-3hwp

ADVISORYhttps://lgtm.com/query/8609731774537641779/

ADVISORYhttps://www.npmjs.com/package/fast-csv

All References (12)

→

https://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829ePatch · Third Party Advisory

→

https://github.com/C2FO/fast-csv/issues/540Third Party Advisory

→

https://github.com/C2FO/fast-csv/security/advisories/GHSA-8cv5-p934-3hwpThird Party Advisory

→

https://lgtm.com/query/8609731774537641779/Exploit · Third Party Advisory

→

https://www.npmjs.com/package/%40fast-csv/parse

→

https://www.npmjs.com/package/fast-csvProduct · Third Party Advisory

→

https://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829ePatch · Third Party Advisory

→

https://github.com/C2FO/fast-csv/issues/540Third Party Advisory

→

https://github.com/C2FO/fast-csv/security/advisories/GHSA-8cv5-p934-3hwpThird Party Advisory

→

https://lgtm.com/query/8609731774537641779/Exploit · Third Party Advisory

→

https://www.npmjs.com/package/%40fast-csv/parse

→

https://www.npmjs.com/package/fast-csvProduct · Third Party Advisory

Quick Facts

CVE IDCVE-2020-26256

CVSS Score6.5 / 10

SeverityMEDIUM

WeaknessCWE-400

CISA KEVNo

Affected1 vendor(s)

PublishedDec 8, 2020

Related CVEs (CWE-400)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2020-26256 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.

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