How severe is CVE-2026-69355?

CVE-2026-69355 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-2026-69355 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.

What products are affected by CVE-2026-69355?

CVE-2026-69355 primarily affects Microsoft Exchange Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-69355?

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-2026-69355 published?

CVE-2026-69355 was published on 2026-09-08 and last updated on 2026-09-30.

CVE-2026-69355

CVE-2026-69355 is a high-severity vulnerability in Microsoft Exchange Server 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-73.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-73
Affected product: Microsoft Exchange Server
Published: 2026-09-08
Last modified: 2026-09-30

Description

External control of file name or path in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

Frequently asked questions

What is CVE-2026-69355?: External control of file name or path in Microsoft Exchange Server allows an authorized attacker to execute code over a network.
How severe is CVE-2026-69355?: CVE-2026-69355 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-2026-69355 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.
What products are affected by CVE-2026-69355?: CVE-2026-69355 primarily affects Microsoft Exchange Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-69355?: 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-2026-69355 published?: CVE-2026-69355 was published on 2026-09-08 and last updated on 2026-09-30.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69355

Affected products (4)

cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_23:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_14:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_15:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server_subscription_edition:*:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Exchange Server

CVE-2007-0213 — Critical (CVSS 10.0): Microsoft Exchange Server 2000 SP3, 2003 SP1 and SP2, and 2007 does not properly decode certain MIME encoded e-mails,…
CVE-2004-0840 — Critical (CVSS 10.0): The SMTP (Simple Mail Transfer Protocol) component of Microsoft Windows XP 64-bit Edition, Windows Server 2003, Windows…
CVE-2004-0574 — Critical (CVSS 10.0): The Network News Transfer Protocol (NNTP) component of Microsoft Windows NT Server 4.0, Windows 2000 Server, Windows…
CVE-1999-0385 — Critical (CVSS 10.0): The LDAP bind function in Exchange 5.5 has a buffer overflow that allows a remote attacker to conduct a denial of…
CVE-2024-21410 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability
CVE-2023-21709 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability

All CVEs affecting Microsoft Exchange Server →

Other CWE-73 vulnerabilities

CVE-2026-101148 — Critical (CVSS 10.0): The BackupSheep WordPress Backup Plugin WordPress plugin through 1.8 does not properly validate its integration key,…
CVE-2026-20358 — Critical (CVSS 10.0): As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Crosswork engineering team…
CVE-2026-50148 — Critical (CVSS 10.0): Metabase is an open-source business intelligence and embedded analytics tool. From 1.54.0 until 1.54.24, 1.55.24,…
CVE-2025-71338 — Critical (CVSS 10.0): Flowise through 2.2.7 fails to sanitize path segments in the document-store loader endpoint, allowing unauthenticated…
CVE-2026-39907 — Critical (CVSS 10.0): Unisys WebPerfect Image Suite versions 3.0.3960.22810 and 3.0.3960.22604 expose an unauthenticated WCF SOAP endpoint on…
CVE-2026-27211 — Critical (CVSS 10.0): Cloud Hypervisor is a Virtual Machine Monitor for Cloud workloads. Versions 34.0 through 50.0 arevulnerable to…

Browse all CWE-73 vulnerabilities →