CVE-2020-15690Public exploitNetwork attack vector

FTP command injection via unchecked CRLF characters

Published Jan 30, 2021 · Updated Aug 4, 2024

CRLF injection in Nim asyncftpclient before 1.2.6 allows attackers to inject arbitrary FTP commands through caller-controlled arguments. The send(ftp, msg) procedure appends a protocol terminator and transmits msg without rejecting embedded carriage returns or line feeds. Exploitation requires an application to pass attacker-controlled values, such as an FTP username or password, into the client; injected commands then execute on the connected FTP server.

CVSS severity9.8
Critical
EPSS probability3.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CRLF injection in Nim asyncftpclient before 1.2.6 allows attackers to inject arbitrary FTP commands through caller-controlled arguments. The send(ftp, msg) procedure appends a protocol terminator and transmits msg without rejecting embedded carriage returns or line feeds. Exploitation requires an application to pass attacker-controlled values, such as an FTP username or password, into the client; injected commands then execute on the connected FTP server.

The record

CVE
CVE-2020-15690
Published
Jan 30, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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