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Public proof of concept

CVE-2018-3953

A public proof of concept exists; no exploitation attested.

  • Published2018-10-17
  • WeaknessCWE-78

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Devices in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04) are susceptible to OS command injection vulnerabilities due to improper filtering of data passed to and retrieved from NVRAM. Data entered into the 'Router Name' input field through the web portal is submitted to apply.cgi as the value to the 'machine_name' POST parameter. When the 'preinit' binary receives the SIGHUP signal, it enters a code path that continues until it reaches offset 0x0042B5C4 in the 'start_lltd' function. Within the 'start_lltd' function, a 'nvram_get' call is used to obtain the value of the user-controlled 'machine_name' NVRAM entry. This value is then entered directly into a command intended to write the host name to a file and subsequently executed.

Timeline

dates in UTC
  1. 2018-10-1702:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 03:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-3953?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-3953?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Linksys e1200 firmwareversion to verify
BranchAffectedFixed in
2.0= 2.0.09no fix published
Linksys e2500 firmwareversion to verify
BranchAffectedFixed in
3.0= 3.0.04no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
2 modulesexploit/linux/http/linksys_e1500_apply_execrank: excellentauxiliary/admin/http/linksys_e1500_e2500_execrank: normalModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Published
2018-10-17
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-frx4-39mr-82xv

Frequently asked questions

What is CVE-2018-3953?

Devices in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04) are susceptible to OS command injection vulnerabilities due to improper filtering of data passed to and retrieved from NVRAM. Data entered into the 'Router Name' input field through the web portal is submitted to apply.cgi as the value to the 'machine_name' POST parameter. When the 'preinit' binary receives the SIGHUP signal, it enters a code path that continues until it reaches offset 0x0042B5C4 in the 'start_lltd' function. Within the 'start_lltd' function, a 'nvram_get' call is used to obtain the value of the user-controlled 'machine_name' NVRAM entry. This value is then entered directly into a command intended to write the host name to a file and subsequently executed.

Is CVE-2018-3953 actively exploited?

Active exploitation of CVE-2018-3953 has not been confirmed. Its EPSS score was 13.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-3953?

CVE-2018-3953 has a CVSS v3 base score of 7.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record