CVE-2020-29548Public exploitNetwork attack vector

Session command injection via STLS pipelining

Published Aug 17, 2021 · Updated Aug 4, 2024

Command injection in SmarterTools SmarterMail 100.0.7537 and earlier allows man-in-the-middle attackers to inject POP3 commands after STLS. The POP3 STLS transition leaves pipelined plaintext bytes buffered and processes them as commands inside the encrypted user session. Exploitation requires an active network position between the client and server; injected commands execute within the victim's authenticated POP3 session.

CVSS severity8.1
High
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in SmarterTools SmarterMail 100.0.7537 and earlier allows man-in-the-middle attackers to inject POP3 commands after STLS. The POP3 STLS transition leaves pipelined plaintext bytes buffered and processes them as commands inside the encrypted user session. Exploitation requires an active network position between the client and server; injected commands execute within the victim's authenticated POP3 session.

The record

CVE
CVE-2020-29548
Published
Aug 17, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-77, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1557Adversary-in-the-Middle

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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