How severe is CVE-2019-10691?

CVE-2019-10691 has a CVSS 3.x base score of 7.5, rated high 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 high.

Is CVE-2019-10691 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-10691?

CVE-2019-10691 primarily affects Dovecot. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-10691?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-10691 published?

CVE-2019-10691 was published on 2019-04-24 and last updated on 2026-06-17.

CVE-2019-10691

CVE-2019-10691 is a high-severity vulnerability in Dovecot with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Dovecot
Published: 2019-04-24
Last modified: 2026-06-17

Description

The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate with an invalid UTF-8 sequence as the username.

Frequently asked questions

What is CVE-2019-10691?: The JSON encoder in Dovecot before 2.3.5.2 allows attackers to repeatedly crash the authentication service by attempting to authenticate with an invalid UTF-8 sequence as the username.
How severe is CVE-2019-10691?: CVE-2019-10691 has a CVSS 3.x base score of 7.5, rated high 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 high.
Is CVE-2019-10691 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-10691?: CVE-2019-10691 primarily affects Dovecot. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-10691?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-10691 published?: CVE-2019-10691 was published on 2019-04-24 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*

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