How severe is CVE-2026-9399?

CVE-2026-9399 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-9399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-9399?

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.

Does CVE-2026-9399 have an EU (EUVD) identifier?

Yes. CVE-2026-9399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31600.

When was CVE-2026-9399 published?

CVE-2026-9399 was published on 2026-05-24 and last updated on 2026-06-17.

CVE-2026-9399

CVE-2026-9399 is a high-severity vulnerability with a CVSS 3.x base score of 8.8. 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-119.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 9.0
CVSS v4: 7.4
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31600
Weakness: CWE-119
Published: 2026-05-24
Last modified: 2026-06-17

Description

A vulnerability was detected in Edimax BR-6675nD 1.12. This vulnerability affects the function formsetPPPoE of the file /goform/formsetPPPoE of the component POST Request Handler. Performing a manipulation of the argument pppUserName results in buffer overflow. It is possible to initiate the attack remotely. The exploit is now public 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-2026-9399?: A vulnerability was detected in Edimax BR-6675nD 1.12. This vulnerability affects the function formsetPPPoE of the file /goform/formsetPPPoE of the component POST Request Handler. Performing a manipulation of the argument pppUserName results in buffer overflow. It is possible to initiate the attack remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-9399?: CVE-2026-9399 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-9399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-9399?: 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.
Does CVE-2026-9399 have an EU (EUVD) identifier?: Yes. CVE-2026-9399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31600.
When was CVE-2026-9399 published?: CVE-2026-9399 was published on 2026-05-24 and last updated on 2026-06-17.

References

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

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CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

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