How severe is CVE-2020-28896?

CVE-2020-28896 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-28896 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-28896?

CVE-2020-28896 primarily affects Mutt. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-28896?

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

When was CVE-2020-28896 published?

CVE-2020-28896 was published on 2020-11-23 and last updated on 2026-06-17.

CVE-2020-28896

CVE-2020-28896 is a medium-severity vulnerability in Mutt 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-287.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 2.6
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Mutt
Published: 2020-11-23
Last modified: 2026-06-17

Description

Mutt before 2.0.2 and NeoMutt before 2020-11-20 did not ensure that $ssl_force_tls was processed if an IMAP server's initial server response was invalid. The connection was not properly closed, and the code could continue attempting to authenticate. This could result in authentication credentials being exposed on an unencrypted connection, or to a machine-in-the-middle.

Frequently asked questions

What is CVE-2020-28896?: Mutt before 2.0.2 and NeoMutt before 2020-11-20 did not ensure that $ssl_force_tls was processed if an IMAP server's initial server response was invalid. The connection was not properly closed, and the code could continue attempting to authenticate. This could result in authentication credentials being exposed on an unencrypted connection, or to a machine-in-the-middle.
How severe is CVE-2020-28896?: CVE-2020-28896 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-28896 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-28896?: CVE-2020-28896 primarily affects Mutt. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-28896?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-28896 published?: CVE-2020-28896 was published on 2020-11-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mutt:mutt:*:*:*:*:*:*:*:*
cpe:2.3:a:neomutt:neomutt:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

More vulnerabilities in Mutt

CVE-2018-14362 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c does not forbid characters that may…
CVE-2018-14359 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They have a buffer overflow via base64…
CVE-2018-14358 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/message.c has a stack-based buffer…
CVE-2018-14357 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute…
CVE-2018-14356 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c mishandles a zero-length UID.
CVE-2018-14354 — Critical (CVSS 9.8): An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They allow remote IMAP servers to execute…

All CVEs affecting Mutt →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →