Threats / Microsoft / CVE-2024-21410
CVE-2024-21410
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Exchange Server vulnerability
Microsoft Exchange Server privilege escalation vulnerability (CWE-287: Improper Authentication) enabling unauthorized elevation of privileges. Actively exploited in the wild.
Verdict
Today item — known-exploited.
An authentication bypass or improper credential validation flaw in Exchange Server permits attackers to escalate privileges without proper authorization. Active exploitation indicates immediate risk to unpatched deployments.
CISA KEV Yes · 2024-02-155EPSS 0.12661 (verify live)6CVSS 9.83CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2024-02-15).
Probability (EPSS)
EPSS 0.12661 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C) · Affected: Microsoft, Exchange Server. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-287 Improper Authentication — weakness family: Authentication.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 2 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I exploit the authentication weakness to bypass credential validation on the Exchange Server.
Business
Attackers gain unauthorized administrative access to email infrastructure, enabling data theft and system compromise.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I escalate my privileges from a low-level account to administrative level using the vulnerability.
Business
Compromised email systems allow attackers to access sensitive communications, modify mailbox rules, and establish persistence.
3
Lateral reach — past segmentation narrative 3
Attacker
I maintain control over the Exchange environment by leveraging elevated privileges to create backdoor accounts.
Business
Attackers retain long-term access to critical business communications and can exfiltrate confidential data.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05