What is CVE-2018-20503?

CVE-2018-20503 is a medium-severity vulnerability in Alliedtelesis 8100l\/8, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2019-05-07.

How severe is CVE-2018-20503?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2018-20503 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Alliedtelesis 8100l\/8

CVE-2018-20503

Allied Telesis 8100L/8 devices allow XSS via the edit-ipv4_interface.php vlanid or subnet_mask parameter.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2019-05-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.039 (89.9th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.039 · newest: 0.039 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

packetstormsecurity.com/files/151327/SirsiDynix-e-Library-3.5.x-Cross-Site-Scri… (Exploit, VDB Entry, Third Party Advisory)
www.exploit-db.com/exploits/46237/ (Exploit, VDB Entry, Third Party Advisory)
pentest.com.tr/exploits/Allied-Telesis-8100L-8-Cross-Site-Scripting.html (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2018-20503?: CVE-2018-20503 is a medium-severity vulnerability in Alliedtelesis 8100l\/8, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2019-05-07.
How severe is CVE-2018-20503?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2018-20503 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.