CVE-2026-27016
CVE-2026-27016 — LibreNMS has Stored XSS in Custom OID - unit parameter missing strip_tags()
LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Versions 24.10.0 through 26.1.1 are vulnerable to Stored XSS via the unit parameter in Custom OID. The Custom OID functionality lacks strip_tags() sanitization while other fields (name, oid, datatype) are sanitized. The unsanitized value is stored in the database and rendered without HTML escaping. This issue is fixed in version 26.2.0.
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
chance of exploitation in 30 days
CVSS base
5.4
MEDIUM
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 5.4 | CVSS 3.1 | MEDIUM | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-79
- CWE-116
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /MySQL/SNMP.
References
4 on the record
- github.com/librenms/librenms/security/advisories/GHSA-fqx6-693c-f55g
x_refsource_CONFIRM
- github.com/librenms/librenms/pull/19040
x_refsource_MISC
- github.com/librenms/librenms/commit/3bea263e02441690c01dea7fa3fe6ffec94af335
x_refsource_MISC
- github.com/librenms/librenms/releases/tag/26.2.0
x_refsource_MISC
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.