CVE-2021-38703Public exploitNetwork attack vector

Root command execution via syslog configuration injection

Published Sep 1, 2021 · Updated Aug 4, 2024

Command injection in KPN Experia WiFi firmware 1.00.15 allows remote authenticated users to execute commands through the syslog form. The apply_abstract.cgi handler inserts the submitted logging-level value into /tmp/syslog-ng-client.conf without sanitization, allowing a crafted syslog-ng program source to run commands. Access to the management interface and a valid session token are required, although CVE-2021-20090 can bypass that gate; commands run as root.

CVSS severity8.8
High
EPSS probability4.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Command injection in KPN Experia WiFi firmware 1.00.15 allows remote authenticated users to execute commands through the syslog form. The apply_abstract.cgi handler inserts the submitted logging-level value into /tmp/syslog-ng-client.conf without sanitization, allowing a crafted syslog-ng program source to run commands. Access to the management interface and a valid session token are required, although CVE-2021-20090 can bypass that gate; commands run as root.

The record

CVE
CVE-2021-38703
Published
Sep 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 1, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.0NIST NVDAV:N/AC:L/Au:S/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

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

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1059.004Unix Shell

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo