CVE-2026-19135Disclosure

LOWCVSS 5.4 · MEDIUM

Exploit discussion active in current signal (3 latest mentions)

Immediate actions

Patch affected systems immediately
Hunt for exploitation attempts and persistence artifacts
Increase monitoring for publicly documented tradecraft

Recommended action window: High priority (within 72h)

NVD description

A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to the Measurements REST API that escapes the sandbox and loads arbitrary Java classes on the server. This can potentially allow an attacker to gain access to confidential information and compromise integrity. The solution is to upgrade to Meridian 2024.3.12, 2025.0.9 and Horizon 36.0.3 or newer. Meridian and Horizon installation instructions state that they are intended for installation within an organization's private networks and should not be directly accessible from the Internet.

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2.0/ 10 priority

Sources & remediation

Other references

https://github.com/OpenNMS/opennms/pull/8754

Weakness type (CWE)

CWE-470

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

NONE

Threat summary

Public PoC is present in monitored signal
Patch or workaround signal is available
3 mentions across 1 observed day

What's happening

PoC mentioned or linked in 1 signal
Patch or workaround mentioned in 1 signal
Technical details provided in 3 signals
Disclosure: 2 classified signals
3 total mentions across 1 day

Deep dive

Activity timeline3 mentions / 1d

Signal classification2 categories

Disclosure

266.7%

Patch

133.3%

Referenced assets3 URLs

By indicator

Full discourse3 posts

HOL@HashgraphOnline45d
Patch
CVE-2026-19135: a JEXL sandbox bypass in OpenNMS's Measurements REST API lets a low-privileged user load arbitrary Java classes on the server (CVSS 5.4, CWE-470). It is a sandbox escape, not a direct injection. Fixed in Horizon 36.0.3 and Meridian 2024.3.12 / 2025.0.9. https://hol.org/blog/cve-2026-19135-opennms-jexl-measurement-sandbox-bypass
Post summary
CVE-2026-19135 is a JEXL sandbox bypass in OpenNMS allowing low‑privileged users to load arbitrary Java classes (CVSS 5.4, CWE‑470). It has been fixed in Horizon 36.0.3 and Meridian 2024.3.12/2025.0.9.
01061904
19.2K followersView on X
Infoflowcloud@infoflowcloud45d
Disclosure
🚨*CVE* CVE-2026-19135 A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to t… https://www.cve.org/CVERecord?id=CVE-2026-19135 ----- Traducción: CVE-2026-19135 Exi… https://infoflow.cloud`
Post summary
CVE-2026-19135 describes a low‑privileged authenticated user bypass of a JEXL expression sandbox in OpenNMS Meridian and Horizon; no PoC, tool, exploitation report, or patch is referenced.
0000027
97 followersView on X
CVE@CVEnew45d
Disclosure
CVE-2026-19135 A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to t… https://www.cve.org/CVERecord?id=CVE-2026-19135
Post summary
The note announces a sandbox bypass in OpenNMS Meridian and Horizon that lets low‑privileged authenticated users submit crafted JEXL expressions; no exploitation, PoC, or patch details are provided.
00000823
57.9K followersView on X

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