Loytec LINX firmware: Unauthenticated stored XSS in OPC XML-DA server

published 2026-07-24 3 mo ago modified 2026-07-27 3 mo ago also EUVD-2026-48589

cvss: 8.7; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

Stored Cross-Site Scripting (CWE-79) in the OPC XML-DA server statistics in Loytec LIP-ME201C, L-INX, L-GATE, L-ROC, L-IOB, L-DALI, L-VIS and L-PAD through 8.4.16 on LINX-A64 allows an unauthenticated remote attacker to execute arbitrary JavaScript in an administrator's browser (session hijacking, credential theft, device reconfiguration) via a crafted `User-Agent` header in a `POST /da` request.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 3 mo ago (2026-07-24)

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Loytec LIP-ME20xC
Loytec L-INX
Loytec L-GATE
Loytec L-ROC
Loytec L-IOB
Loytec L-DALI
Loytec L-VIS
Loytec L-PAD

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-116 Improper Encoding or Escaping of Output

References

loytec.com /support/product-security/advisories/8522-dibt-cve-20260526-0004-unauthenticated-stored-xxs-in-opc-xml-da-serv
vendor-advisory

Sources

CVE List CVE-2026-12496
NVD CVE-2026-12496

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary