CVE-2019-16239

process_http_response in OpenConnect before 8.05 has a Buffer Overflow when a malicious server uses HTTP chunked encoding with crafted chunk sizes.

Published: 2019-09-17 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-16239 is rated High Risk (75.2/100): CVSS Critical severity, with high exploitation likelihood (EPSS 8.53%, 92th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +3.74% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize 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-2019-16239

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 2025-12-28 4.78% 8.53% +3.74%
2 2025-12-27 8.53% 4.78% -3.74%
3 2025-10-28 — 8.53% —

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-16239

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2019-16239

OS Trackers for CVE-2019-16239

vendor priority summary link
debian not yet assigned CVE-2019-16239 not yet assigned priority: Debian including 1 source packages (openconnect), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-16239
suse medium CVE-2019-16239 severity moderate: SUSE including 24 source package names (libopenconnect5-9.12-2.1, openconnect-7.08-3.4.1, …), 60 product×package rows across 22 product lines (SUSE Linux Enterprise Desktop 12 SP4, SUSE Linux Enterprise Module for Open Buildservice Development Tools 15 SP2, … (22 product lines)): Fixed 60. https://www.suse.com/security/cve/CVE-2019-16239/
ubuntu medium CVE-2019-16239 medium priority: Ubuntu including 1 source packages (openconnect), 12 status rows across 12 suites (bionic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, trusty, upstream, xenial): ignored 5, not-affected 4, released 2, DNE 1. https://ubuntu.com/security/CVE-2019-16239

Affected software / configurations for CVE-2019-16239

Vendor Product Version Raw CPE
infradead openconnect < 8.05 cpe:2.3:a:infradead:openconnect:*:*:*:*:*:*:*:*
fedoraproject fedora 29 cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
opensuse leap 15.0 cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

References for CVE-2019-16239

URL Tags
http://lists.infradead.org/pipermail/openconnect-devel/2019-September/005412.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00060.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00061.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2019/10/msg00003.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FX56KYWC7X4ETV4P6HGJC7GZUEBITBBS/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HDMZGNBLZZKAGBI2PNXYWWKLD2LXKFH6/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WI7ZENFAWCHF2RU4NHPL2CU4WGZ4BNDJ/
https://seclists.org/bugtraq/2020/Jan/31 Mailing List Third Party Advisory
https://t2.fi/schedule/2019/ Not Applicable
https://usn.ubuntu.com/4565-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4607 Third Party Advisory
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