CVE-2020-10957Public exploitNetwork attack vector

Unauthenticated service crash via malformed NOOP parameters

Published May 18, 2020 · Updated Aug 4, 2024

NULL pointer dereference in Dovecot 2.3.0 through 2.3.10 allows remote attackers to crash submission services via malformed NOOP parameters. smtp-server-cmd-noop.c accepts a NULL parameter result from SMTP syntax parsing and dereferences it instead of rejecting the malformed input. No authentication or user interaction is required; repeated requests can keep submission-login unavailable, while LMTP is usually shielded by a trusted MTA.

CVSS severity7.5
High
EPSS probability7.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Dovecot 2.3.0 through 2.3.10 allows remote attackers to crash submission services via malformed NOOP parameters. smtp-server-cmd-noop.c accepts a NULL parameter result from SMTP syntax parsing and dereferences it instead of rejecting the malformed input. No authentication or user interaction is required; repeated requests can keep submission-login unavailable, while LMTP is usually shielded by a trusted MTA.

The record

CVE
CVE-2020-10957
Published
May 18, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 18, 2020CVE 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

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Open-XchangeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5MITRECVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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