CVE-2026-87692 — Microsoft Exchange Server Elevation of Privilege Vulnerability
Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 1.6% (30-day exploitation probability)+11
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Microsoft Microsoft Exchange Server 2016 Cumulative Update 23, Microsoft Microsoft Exchange Server 2019 Cumulative Update 14, Microsoft Microsoft Exchange Server Subscription Edition RTM).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 | ≥ 15.01.0.0 and < 15.01.2507.077 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 14 | ≥ 15.02.0.0 and < 15.02.1544.050 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Microsoft | Microsoft Exchange Server Subscription Edition RTM | ≥ 15.02.0.0 and < 15.02.2562.056 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | secure@microsoft.com via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | microsoft via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: secure@microsoft.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Monitor serialized objects in requests and unexpected processes spawned by the runtime.
Timeline
What happened to this CVE, newest first.
- 2026
- Source status changed · Awaiting Analysis → Undergoing Analysis
- SSVC assessment updated
- Affected products added · microsoft/microsoft exchange server 2016 cumulative update 23, microsoft/microsoft exchange server 2019 cumulative updat
- Record published
- CVSS changed · 7.8
- Source status changed · → Awaiting Analysis
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-87695 Microsoft Exchange Server Elevation of Privilege Vulnerability 2d
- High CVE-2026-87696 Microsoft Exchange Server Elevation of Privilege Vulnerability 2d
- High CVE-2026-77910 Microsoft Exchange Server Elevation of Privilege Vulnerability 2d
- High CVE-2026-70571 Microsoft Exchange Server Remote Code Execution Vulnerability 2d
- Critical CVE-2026-70279 Microsoft Exchange Server Spoofing Vulnerability 2d
- High CVE-2026-96940 Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate... 13d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-87692 is "Microsoft Exchange Server Elevation of Privilege Vulnerability", rated High. It affects Microsoft Exchange Server 2016 Cumulative Update 23 (Microsoft); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 1.59% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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