CVE & CISA-KEV Catalog

CVE-2026-55007

HIGH
8.1
CVSS v3
NVD

Description

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

How to fix

Remediation Available
Microsoft Exchange Server 2019 Cumulative Update 14Microsoft
Install:KB5121610
Microsoft Exchange Server 2019 Cumulative Update 15Microsoft
Install:KB5121609
Microsoft Exchange Server Subscription Edition RTMMicrosoft
Install:KB5121608Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Exploit Intelligence

0.73%probability of exploitation in 30 days
52ndpercentile

Moderate risk: more likely to be exploited than 52% of all known CVEs.

References

Other references1

Related Vulnerabilities

Other CWE-415 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-25136Medium6.590%-Fix
CVE-2003-0545Critical9.887%-Fix
CVE-2018-0101Critical10.087%-Fix
CVE-2026-33824Critical9.873%KEVFix
CVE-2019-3829Medium5.359%-Fix
CVE-2021-3407Medium5.550%-Fix

Common questions

How do I fix CVE-2026-55007?

Published advisories record a fix for 3 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-55007 being actively exploited?

Not that we know of. CVE-2026-55007 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.73% is the estimated probability that it will be exploited in the next 30 days. That is higher than 52% of all scored CVEs.

How severe is CVE-2026-55007?

CVE-2026-55007 has a CVSS v3 base score of 8.1, rated important. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-55007 affect?

Published advisories record a fix for Microsoft Exchange Server 2019 Cumulative Update 14 (Microsoft), Microsoft Exchange Server 2019 Cumulative Update 15 (Microsoft), Microsoft Exchange Server Subscription Edition RTM (Microsoft). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-09.