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CVE-2021-26858

Microsoft Exchange Server Remote Code Execution Vulnerability

Published
Last modified
published
Listed in CISA KEV
Fix
Fixed in 15.00.1395.012, 15.00.1473.006, 15.00.1497.012, 15.01.1531.012, 15.01.1591.018, and 19 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: active
  • Automatable: yes
  • Technical impact: total

Summary

Microsoft Exchange Server, the email and collaboration server software used by organizations, is affected by this vulnerability. An attacker who exploits it could potentially run malicious code on the affected server, which could allow them to take control of the system.

Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.

Read the original description

Microsoft Exchange Server Remote Code Execution Vulnerability

Timeline

  1. CVE published
  2. Added to CISA KEV

    CISA has evidence of exploitation in the wild

  3. CISA remediation deadline

    Due date for US federal agencies to patch

  4. CISA SSVC assessment

    Exploitation: active · Automatable: yes · Technical impact: total

  5. Record last updated
  6. EPSS reached 10%

    FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

  • Microsoft Microsoft Exchange Server 2013 Cumulative Update 21

    From 15.00.0 · fixed in 15.00.1395.012

  • Microsoft Microsoft Exchange Server 2013 Cumulative Update 22

    From 15.00.0 · fixed in 15.00.1473.006

  • Microsoft Microsoft Exchange Server 2013 Cumulative Update 23

    From 15.00.0 · fixed in 15.00.1497.012

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 10

    From 15.01.0 · fixed in 15.01.1531.012

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 11

    From 15.01.0 · fixed in 15.01.1591.018

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 12

    From 15.01.0 · fixed in 15.01.1713.010

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 13

    From 15.01.0 · fixed in 15.01.1779.008

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 14

    From 15.01.0 · fixed in 15.01.1847.012

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 15

    From 15.01.0 · fixed in 15.01.1913.012

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 16

    From 15.01.0 · fixed in 15.01.1979.008

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 17

    From 15.01.0 · fixed in 15.01.2044.013

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 18

    From 15.01.0 · fixed in 15.01.2106.013

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 19

    From 15.01.0 · fixed in 15.01.2176.009

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 8

    From 15.01.0 · fixed in 15.01.1415.010

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 9

    From 15.01.0 · fixed in 15.01.1466.016

  • Microsoft Microsoft Exchange Server 2019

    From 15.02.0 · fixed in 15.02.0221.018

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 1

    From 15.02.0 · fixed in 15.01.1979.006

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 2

    From 15.02.0 · fixed in 15.02.0397.011

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 3

    From 15.02.0 · fixed in 15.02.0464.015

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 4

    From 15.02.0 · fixed in 15.02.0659.012

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 5

    From 15.02.0 · fixed in 15.02.0595.008

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 6

    From 15.02.0 · fixed in 15.02.0529.013

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 7

    From 15.02.0 · fixed in 15.02.0721.013

  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 8

    From 15.02.0 · fixed in 15.02.0792.010

References 1

msrc.microsoft.com