CVE-2020-5738Public exploitNetwork attack vector

Authenticated root code execution via symlink tar extraction

Published Apr 14, 2020 · Updated Aug 4, 2024

Link following in Grandstream GXP1600 Series firmware 1.0.4.152 and earlier allows remote authenticated users to execute code as root. The upload_vpntar endpoint extracts an uploaded archive into /var/user/openvpn/ while honoring embedded symlinks, allowing later entries to overwrite the writable root crontab. Access requires credentials for the phone's HTTP interface; successful exploitation runs attacker-controlled scripts with root privileges.

CVSS severity8.8
High
EPSS probability5.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Link following in Grandstream GXP1600 Series firmware 1.0.4.152 and earlier allows remote authenticated users to execute code as root. The upload_vpntar endpoint extracts an uploaded archive into /var/user/openvpn/ while honoring embedded symlinks, allowing later entries to overwrite the writable root crontab. Access requires credentials for the phone's HTTP interface; successful exploitation runs attacker-controlled scripts with root privileges.

The record

CVE
CVE-2020-5738
Published
Apr 14, 2020
Updated
Aug 4, 2024
Vendor
Grandstream Networks
Product
GXP1600 Series
Classifications
CWE-59, CAPEC-132, T1190, T1053.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2020CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.4.152 and below

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Grandstream Networks · GXP1600 Seriesversion=1.0.4.152 and below

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.0NVDAV:N/AC:L/Au:S/C:C/I:C/A:C

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

CWE-59Improper Link Resolution Before File Access ('Link Following')
CAPEC-132Symlink Attack
T1190Exploit Public-Facing Application
T1053.003Scheduled Task/Job: Cron

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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