How severe is CVE-2026-103558?

CVE-2026-103558 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-103558 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-103558?

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-2026-103558 published?

CVE-2026-103558 was published on 2026-10-13 and last updated on 2026-10-16.

CVE-2026-103558

CVE-2026-103558 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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-833.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-833
Published: 2026-10-13
Last modified: 2026-10-16

Description

Deadlock in Windows Routing and Remote Access Service (RRAS) allows an unauthorized attacker to deny service over a network.

Frequently asked questions

What is CVE-2026-103558?: Deadlock in Windows Routing and Remote Access Service (RRAS) allows an unauthorized attacker to deny service over a network.
How severe is CVE-2026-103558?: CVE-2026-103558 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-103558 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-103558?: 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-2026-103558 published?: CVE-2026-103558 was published on 2026-10-13 and last updated on 2026-10-16.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103558

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