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Vulnerability record · CVE-2020-10957 · published 18 May 2020

CVE-2020-10957: Dovecot null pointer dereference vulnerability

Dovecot · Dovecot

In Dovecot before 2.3.10.1, unauthenticated sending of malformed parameters to a NOOP command causes a NULL Pointer Dereference and crash in submission-login, submission, or lmtp.

7.5 CVSS 3.1 High EPSS 7.2% · top 5.9% CWE-476 · NULL pointer dereference
7.5CVSS 3.1 base score, v2 5.0
7.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
20References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

In Dovecot before 2.3.10.1, unauthenticated sending of malformed parameters to a NOOP command causes a NULL Pointer Dereference and crash in submission-login, submission, or lmtp.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00059.html
http://packetstormsecurity.com/files/157771/Open-Xchange-Dovecot-2.3.10-Null-Pointer-Dereference-Denial-Of-Service.html
http://seclists.org/fulldisclosure/2020/May/37 ExploitThird Party Advisory
http://www.openwall.com/lists/oss-security/2020/05/18/1 Mailing ListThird Party Advisory
https://dovecot.org/security Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TTZN2VW55ZC2AQBGBJMLRJS
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VVUWHUUAFPC6XGIXYFIPTNB
https://usn.ubuntu.com/4361-1/
https://www.debian.org/security/2020/dsa-4690
https://www.openwall.com/lists/oss-security/2020/05/18/1 Mailing ListThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00059.html
http://packetstormsecurity.com/files/157771/Open-Xchange-Dovecot-2.3.10-Null-Pointer-Dereference-Denial-Of-Service.html
http://seclists.org/fulldisclosure/2020/May/37 ExploitThird Party Advisory
http://www.openwall.com/lists/oss-security/2020/05/18/1 Mailing ListThird Party Advisory
https://dovecot.org/security Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TTZN2VW55ZC2AQBGBJMLRJS
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VVUWHUUAFPC6XGIXYFIPTNB
https://usn.ubuntu.com/4361-1/
https://www.debian.org/security/2020/dsa-4690
https://www.openwall.com/lists/oss-security/2020/05/18/1 Mailing ListThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2019-11500Dovecot IMAP quoted-string handling out-of-bounds writeDovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2) mishandles '\0' characters during protocol processing of quoted stri…EPSS 63%analysed9.1CVE-2026-27851Dovecot sql injection vulnerabilityWhen safe filter is used with variable expansion, all following pipelines on the same string are incorrectly interpreted as safe too, enabling unsafe…EPSS 0.58%8.8CVE-2022-30550Dovecot improper authentication vulnerabilityAn issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration entries exist with the same driver …EPSS 2.2%8.2CVE-2026-24031Dovecot sql injection vulnerabilityDovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability allows bypassing authentication for…EPSS 0.40%7.8CVE-2019-7524Dovecot memory buffer overflow vulnerabilityIn Dovecot before 2.2.36.3 and 2.3.x before 2.3.5.1, a local attacker can cause a buffer overflow in the indexer-worker process, which can be used to…EPSS 1.2%7.5CVE-2026-27858Dovecot uncontrolled resource consumption vulnerabilityAttacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force…EPSS 1.0%7.5CVE-2026-27857Dovecot uncontrolled resource consumption vulnerabilitySending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnec…EPSS 0.80%7.5CVE-2025-59028Dovecot improper input validation vulnerabilityWhen sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invali…EPSS 0.45%

Source: NIST National Vulnerability Database (record CVE-2020-10957), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.