CVE-2026-69356: Microsoft Exchange Server Spoofing Vulnerability

18

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.8% (30-day exploitation probability)+8
Technical severity (critical)+10

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.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.76%

ahead of 54% of scored CVEs · Oct 14, 2026

Affects

Microsoft

Exchange Server and 5 more

CVSS base

9.3

Critical · 2 source(s)

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.

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — msrc.microsoft.com (NIST National Vulnerability Database)

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 Exchange Server, Microsoft Exchange Server Subscription Edition, Microsoft Microsoft Exchange Server 2016 Cumulative Update 23…).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (cross-site scripting), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Microsoft	Exchange Server	version 2016-cumulative_update_23version 2019-cumulative_update_14version 2019-cumulative_update_15	Vulnerable	NIST National Vulnerability Database
Microsoft	Exchange Server Subscription Edition	< 15.02.2562.049	Vulnerable	NIST National Vulnerability Database
Microsoft	Microsoft Exchange Server 2016 Cumulative Update 23	≥ 15.01.0.0 and < 15.01.2507.073	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Exchange Server 2019 Cumulative Update 14	≥ 15.02.0.0 and < 15.02.1544.046	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Exchange Server 2019 Cumulative Update 15	≥ 15.02.0.0 and < 15.02.1748.051	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Exchange Server Subscription Edition RTM	≥ 15.02.0.0 and < 15.02.2562.049	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

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
9.3	CVSS 3.1	Critical	2.8	5.8	secure@microsoft.com via NIST National Vulnerability Database
9.3	CVSS 3.1	Critical	—	—	microsoft via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N (score shown at the top: secure@microsoft.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-79 · Cross-site Scripting (XSS)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Monitor CSP violation reports and script payloads in reflected parameters.

web/proxy/WAF logsnetwork IDS/IPSapplication logs

Timeline

What happened to this CVE, newest first.

2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
Affected products added · microsoft/exchange server, microsoft/exchange server subscription edition
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · Published → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record published
Oct 14, 2026
CVSS changed · 9.3
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Published
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Record created in this database
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
CVE published
Sep 8, 2026 · microsoft

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

1 on the record

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69356
vendor-advisory, patch, Patch, Vendor Advisory, CVE Program (cve.org) e CISA ADP

Elsewhere on this site

Microsoft
every CVE for this vendor

Cross-site scripting
same class

CWE-79
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-87696 Microsoft Exchange Server Elevation of Privilege Vulnerability 2d
High CVE-2026-87695 Microsoft Exchange Server Elevation of Privilege Vulnerability 2d
High CVE-2026-87692 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

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 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-2026-69356 is "Microsoft Exchange Server Spoofing Vulnerability", rated Critical. It affects Exchange Server (Microsoft); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.3 describes technical severity. EPSS 0.76% 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.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.