How severe is CVE-2026-78861?

CVE-2026-78861 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-78861 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-78861?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-78861 published?

CVE-2026-78861 was published on 2026-10-05 and last updated on 2026-10-06.

CVE-2026-78861

CVE-2026-78861 is a high-severity vulnerability with a CVSS 3.x base score of 7.7. 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-789.

Key facts

Severity: High (CVSS 3.x base score 7.7)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-789
Published: 2026-10-05
Last modified: 2026-10-06

Description

An issue in Mercusys AC12 V2 allows a local attacker to execute arbitrary code via a hardcoded 512-bit RSA Private Key

Frequently asked questions

What is CVE-2026-78861?: An issue in Mercusys AC12 V2 allows a local attacker to execute arbitrary code via a hardcoded 512-bit RSA Private Key
How severe is CVE-2026-78861?: CVE-2026-78861 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-78861 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-78861?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-78861 published?: CVE-2026-78861 was published on 2026-10-05 and last updated on 2026-10-06.

References

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