How severe is CVE-2026-18686?

CVE-2026-18686 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-18686 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-18686?

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

When was CVE-2026-18686 published?

CVE-2026-18686 was published on 2026-08-04 and last updated on 2026-08-12.

CVE-2026-18686

CVE-2026-18686 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. 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-74.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
CVSS v4: 8.9
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Published: 2026-08-04
Last modified: 2026-08-12

Description

A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5. The affected element is the function nas-web.add_user of the file /cgi-bin/glc of the component nas-web RPC Wrapper. Performing a manipulation results in command injection. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure and confirmed the existence of the vulnerability.

Frequently asked questions

What is CVE-2026-18686?: A vulnerability was detected in GL.iNet GL-MT3000 up to 4.4.5. The affected element is the function nas-web.add_user of the file /cgi-bin/glc of the component nas-web RPC Wrapper. Performing a manipulation results in command injection. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure and confirmed the existence of the vulnerability.
How severe is CVE-2026-18686?: CVE-2026-18686 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-18686 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-18686?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-18686 published?: CVE-2026-18686 was published on 2026-08-04 and last updated on 2026-08-12.

References

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