CVE-2020-15591Network attack vector

Unauthenticated code execution via HTTP Host eval

Published Mar 17, 2022 · Updated Aug 4, 2024

Eval injection in fexsrv in F*EX before fex-20160919_2 allows remote attackers to execute arbitrary code through an HTTP request. The bintar path incorporates the attacker-controlled HTTP Host header into a Perl substitution passed as the mod argument to copy(), which executes it with eval. No authentication is required to request xx.tar, so injected Perl runs with the fexsrv process's privileges and can compromise server data and availability.

CVSS severity9.8
Critical
EPSS probability4.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Eval injection in fexsrv in F*EX before fex-20160919_2 allows remote attackers to execute arbitrary code through an HTTP request. The bintar path incorporates the attacker-controlled HTTP Host header into a Perl substitution passed as the mod argument to copy(), which executes it with eval. No authentication is required to request xx.tar, so injected Perl runs with the fexsrv process's privileges and can compromise server data and availability.

The record

CVE
CVE-2020-15591
Published
Mar 17, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 17, 2022CVE 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

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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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