How severe is CVE-2019-12855?

CVE-2019-12855 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2019-12855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-12855?

CVE-2019-12855 affects Twisted. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-12855?

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-2019-12855 published?

CVE-2019-12855 was published on 2019-06-16 and last updated on 2026-06-17.

CVE-2019-12855

CVE-2019-12855 is a high-severity vulnerability in Twisted with a CVSS 3.x base score of 7.4. 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-295.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 5.8
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Twisted
Published: 2019-06-16
Last modified: 2026-06-17

Description

In words.protocols.jabber.xmlstream in Twisted through 19.2.1, XMPP support did not verify certificates when used with TLS, allowing an attacker to MITM connections.

Frequently asked questions

What is CVE-2019-12855?: In words.protocols.jabber.xmlstream in Twisted through 19.2.1, XMPP support did not verify certificates when used with TLS, allowing an attacker to MITM connections.
How severe is CVE-2019-12855?: CVE-2019-12855 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2019-12855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-12855?: CVE-2019-12855 affects Twisted. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-12855?: 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-2019-12855 published?: CVE-2019-12855 was published on 2019-06-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*

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