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Vulnerability record · CVE-2019-12855 · published 16 June 2019

CVE-2019-12855: Twisted improper certificate validation vulnerability

Twisted · Twisted

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.

7.4 CVSS 3.0 High EPSS 1.8% · top 22.3% CWE-295 · Improper certificate validation
7.4CVSS 3.0 base score, v2 5.8
1.8%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
16References
17 Jun 2026Last modified by NVD

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.

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00013.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00028.html
https://github.com/twisted/twisted/pull/1147 PatchThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PLTZDMFBNFSJMBXYJNGJHEN
https://twistedmatrix.com/trac/ticket/9561 Vendor Advisory
https://usn.ubuntu.com/4308-1/
https://usn.ubuntu.com/4308-2/
https://www.oracle.com/security-alerts/cpuapr2020.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00013.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00028.html
https://github.com/twisted/twisted/pull/1147 PatchThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PLTZDMFBNFSJMBXYJNGJHEN
https://twistedmatrix.com/trac/ticket/9561 Vendor Advisory
https://usn.ubuntu.com/4308-1/
https://usn.ubuntu.com/4308-2/
https://www.oracle.com/security-alerts/cpuapr2020.html

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Source: NIST National Vulnerability Database (record CVE-2019-12855), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.