CVE-2026-55007
CVE-2026-55007 is a high-severity vulnerability in Microsoft Exchange Server with a CVSS 3.x base score of 8.1. 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-415.
Key facts
- Severity: High (CVSS 3.x base score 8.1)
- EPSS exploit prediction: 1% (52nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-415
- Affected product: Microsoft Exchange Server
- Published:
- Last modified:
Description
Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
Frequently asked questions
- What is CVE-2026-55007?
- Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
- How severe is CVE-2026-55007?
- CVE-2026-55007 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-55007 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-55007?
- CVE-2026-55007 primarily affects Microsoft Exchange Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-55007?
- 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-2026-55007 published?
- CVE-2026-55007 was published on 2026-09-08 and last updated on 2026-10-05.
References
Affected products (3)
- 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 →
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- CVE-2026-77493 — Critical (CVSS 9.8): Double free in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.
- CVE-2026-64387 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query directory replay…
- CVE-2026-64386 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query_info() replay…