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.

Published: 2019-06-16 Last update: 2024-11-25 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-12855 is rated Moderate Risk (56.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.84%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-12855

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-30 0.65% 0.84% +0.20%
2 2026-04-01 0.66% 0.65% -0.01%
3 2025-11-21 — 0.66% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-12855

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.0 HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2019-12855

GitHub Security Advisory for CVE-2019-12855

GHSA-65rm-h285-5cc5 · Severity: critical · Ecosystem: pip — Improper Certificate Validation in Twisted

OS Trackers for CVE-2019-12855

vendor priority summary link
alpine high CVE-2019-12855: 1 source package rows (py3-twisted); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2019-12855
debian not yet assigned CVE-2019-12855 not yet assigned priority: Debian including 1 source packages (twisted), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-12855
redhat medium — https://access.redhat.com/security/cve/CVE-2019-12855
suse medium CVE-2019-12855 severity moderate: SUSE including 36 source package names (python-Twisted, python-Twisted-15.2.1-9.8.1, …), 44 product×package rows across 19 product lines (HPE Helion OpenStack 8, SUSE Enterprise Storage 4, … (19 product lines)): Fixed 42, Known Not Affected 2. https://www.suse.com/security/cve/CVE-2019-12855/
ubuntu low CVE-2019-12855 low priority: Ubuntu including 2 source packages (twisted, twisted-py3), 14 status rows across 7 suites (bionic, cosmic, disco, eoan, trusty, upstream, xenial): DNE 6, released 4, ignored 2, needs-triage 2. https://ubuntu.com/security/CVE-2019-12855

Affected software / configurations for CVE-2019-12855

Vendor Product Version Raw CPE
twisted twisted <= 19.2.1 cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*

References for CVE-2019-12855

cvelogic Threat Intelligence