EUVD-2026-73178
GHSA-phwr-836j-jgp8
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Pre-auth network-reachable double-free (AV:N/PR:N) with AC:H for required heap-grooming complexity; full C/I/A on successful Exchange service compromise.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
4DescriptionCVE.org
Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.
AnalysisAI
Remote code execution in Microsoft Exchange Server 2019 (CU14, CU15, and Subscription Edition) is possible via a double-free memory corruption vulnerability (CWE-415) exploitable by an unauthenticated remote attacker with no user interaction required. The CVSS vector AC:H signals that exploitation is technically complex, likely requiring precise heap-grooming to control the freed memory region and redirect execution, which constrains opportunistic mass exploitation. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The CVSS PR:N confirms this is a pre-authentication vulnerability - no credentials or session are required to trigger the double-free. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 8.1 score (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) captures two competing signals: the reach (unauthenticated, network-only, no interaction) is maximally dangerous, while AC:H meaningfully reduces exploitation likelihood by requiring complex heap state manipulation that not all threat actors can reliably achieve. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply Microsoft's security update immediately for the installed Exchange Server update track. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all Exchange Server 2019 instances and identify those running CU14, CU15, or Subscription Edition; prioritize affected systems for patching and implement network segmentation to limit email server access if immediate patching is not possible. …
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Same weakness CWE-415 – Double Free
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External POC / Exploit Code
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