How severe is CVE-2026-12209?

CVE-2026-12209 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-12209 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-12209?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-12209 have an EU (EUVD) identifier?

Yes. CVE-2026-12209 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36683.

When was CVE-2026-12209 published?

CVE-2026-12209 was published on 2026-06-15 and last updated on 2026-06-17.

CVE-2026-12209

CVE-2026-12209 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
CVSS v4: 5.5
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-36683
Weakness: CWE-94
Published: 2026-06-15
Last modified: 2026-06-17

Description

A security vulnerability has been detected in RubyLouvre avalon up to 2.2.10. The impacted element is an unknown function of the file src/filters/index.js of the component Template Filter Handler. Such manipulation leads to improperly controlled modification of object prototype attributes. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-12209?: A security vulnerability has been detected in RubyLouvre avalon up to 2.2.10. The impacted element is an unknown function of the file src/filters/index.js of the component Template Filter Handler. Such manipulation leads to improperly controlled modification of object prototype attributes. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-12209?: CVE-2026-12209 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-12209 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-12209?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-12209 have an EU (EUVD) identifier?: Yes. CVE-2026-12209 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36683.
When was CVE-2026-12209 published?: CVE-2026-12209 was published on 2026-06-15 and last updated on 2026-06-17.

References

Other CWE-94 (Code Injection) vulnerabilities

CVE-2026-57624 — Critical (CVSS 10.0): Unauthenticated Remote Code Execution (RCE) in Blocksy Companion Pro <= 2.1.46 versions.
CVE-2026-10134 — Critical (CVSS 10.0): IBM Langflow OSS 1.0.0 through 1.9.3 allows an attacker to read every secret available to the Langflow process, read…
CVE-2026-53576 — Critical (CVSS 10.0): Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, the authentication filter…
CVE-2026-10561 — Critical (CVSS 10.0): IBM Langflow OSS 1.0.0 through 1.9.3 has an vulnerability due to an improper isolation of Python execution combined…
CVE-2026-25470 — Critical (CVSS 10.0): Improper Control of Generation of Code ('Code Injection') vulnerability in ACPT ACPT (Pro) - Custom Post Types Plugin…
CVE-2026-48836 — Critical (CVSS 10.0): Unauthenticated Remote Code Execution (RCE) in Easy Invoice <= 2.1.19 versions.

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