CVE-2020-10967

CVE-2020-10967 is a medium-severity vulnerability in Dovecot with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

• Severity: Medium (CVSS 3.x base score 5.3)
• CVSS v2: 5.0
• EPSS exploit prediction: 8% (94th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-20
• Affected product: Dovecot
• Published: 2020-05-18
• Last modified: 2026-06-17

Description

In Dovecot before 2.3.10.1, remote unauthenticated attackers can crash the lmtp or submission process by sending mail with an empty localpart.

Frequently asked questions

What is CVE-2020-10967?

In Dovecot before 2.3.10.1, remote unauthenticated attackers can crash the lmtp or submission process by sending mail with an empty localpart.

How severe is CVE-2020-10967?

CVE-2020-10967 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2020-10967 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10967?

CVE-2020-10967 affects Dovecot. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-10967?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-10967 published?

CVE-2020-10967 was published on 2020-05-18 and last updated on 2026-06-17.

References

• 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
• http://www.openwall.com/lists/oss-security/2020/05/18/1
• https://dovecot.org/security
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4AAX2MJEULPVSRZOBX3PNPFSYP4FM4TT/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EYZU6CHA3VMYYAUCMHSCCQKJEVEIKPQ2/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TTZN2VW55ZC2AQBGBJMLRJSZIKSB2NS6/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VVUWHUUAFPC6XGIXYFIPTNBXLHPNM4W6/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XKKAL3OMG76ZZ7CIEMQP2K6KCTD2RAKE/
• 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

Affected products (1)

• cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*

More vulnerabilities in Dovecot

• CVE-2019-11500 — Critical (CVSS 9.8): In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can fail for…
• CVE-2022-30550 — High (CVSS 8.8): An issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration…
• CVE-2019-7524 — High (CVSS 8.8): In 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…
• CVE-2026-24031 — High (CVSS 7.7): Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability…
• CVE-2019-3814 — High (CVSS 7.7): It was discovered that Dovecot before versions 2.2.36.1 and 2.3.4.1 incorrectly handled client certificates. A remote…
• CVE-2026-27858 — High (CVSS 7.5): Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount…

All CVEs affecting Dovecot →

Other CWE-20 (Improper Input Validation) vulnerabilities

• CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
• CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
• CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
• CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
• CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
• CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →