Home/CVE/Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newl
CVE

CVE-2020-28021

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newl

Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newline characters into a spool file (which indirectly leads to remote code execution as root) via AUTH= in a MAIL FROM command.

HIGH · CVSS 8.8 EPSS 0.05711
Schedule remediation
  • EPSS percentile: top 9% of all CVEs by exploitation likelihood
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
▤

Affected Products & Versions

1
exim>= 4.00 and < 4.94.2
◈

Detection Rules (IDS/IPS)

3
et-openET EXPLOIT Exim New-Line Injection into Spool Header File Inbound M1 (CVE-2020-28021)attempted-admin
et-openET EXPLOIT Exim New-Line Injection into Spool Header File Inbound M2 (CVE-2020-28021)attempted-admin
et-openET EXPLOIT Exim New-Line Injection into Spool Header File Inbound - Information Disclosure Attempt (CVE-2020-28021)attempted-admin
Open rulesets (ET Open, Snort Community, abuse.ch) link to source. Commercial rulesets are reference-only.
▣

Scoring & Timeline

8.8
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD06 May 2021 · 01:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
⚑

Vendor Advisories

5
suse-csafopenSUSE-SU-2024:10746-1
suse-csafopenSUSE-SU-2021:0753-1
suse-csafopenSUSE-SU-2021:0754-1
suse-csafopenSUSE-SU-2021:0677-1
usnUSN-4934-1
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28021-MAUTH.txtVendor Advisory
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