How severe is CVE-2018-1000831?

CVE-2018-1000831 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-1000831 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-1000831?

CVE-2018-1000831 affects K9mail K-9 Mail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-1000831?

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

When was CVE-2018-1000831 published?

CVE-2018-1000831 was published on 2018-12-20 and last updated on 2026-06-17.

CVE-2018-1000831

Q: What is CVE-2018-1000831?

K9Mail version <= v5.600 contains a XML External Entity (XXE) vulnerability in WebDAV response parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via malicious WebDAV server or intercept the reponse of a valid WebDAV server.

CVE-2018-1000831 is a critical-severity vulnerability in K9mail K-9 Mail with a CVSS 3.x base score of 10.0. 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-611.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 7.5
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-611
Affected product: K9mail K-9 Mail
Published: 2018-12-20
Last modified: 2026-06-17

Description

K9Mail version <= v5.600 contains a XML External Entity (XXE) vulnerability in WebDAV response parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via malicious WebDAV server or intercept the reponse of a valid WebDAV server.

Frequently asked questions

What is CVE-2018-1000831?: K9Mail version <= v5.600 contains a XML External Entity (XXE) vulnerability in WebDAV response parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via malicious WebDAV server or intercept the reponse of a valid WebDAV server.
How severe is CVE-2018-1000831?: CVE-2018-1000831 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-1000831 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-1000831?: CVE-2018-1000831 affects K9mail K-9 Mail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-1000831?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-1000831 published?: CVE-2018-1000831 was published on 2018-12-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:k9mail:k-9_mail:*:*:*:*:*:*:*:*

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