CVE-2019-19330

The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII 0x0), aka Intermediary Encapsulation Attacks.

Published: 2019-11-27 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-19330 is rated High Risk (73.2/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 3.92%). EPSS rose +2.87% 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-2019-19330

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 2026-06-15 1.06% 3.92% +2.87%
2 2026-05-27 0.96% 1.06% +0.10%
3 2026-01-24 — 0.96% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-19330

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-2019-19330

OS Trackers for CVE-2019-19330

vendor priority summary link
debian not yet assigned CVE-2019-19330 not yet assigned priority: Debian including 1 source packages (haproxy), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-19330
gentoo high CVE-2019-19330: 1 GLSA(s) (202004-01), 1 atom(s) (net-proxy/haproxy); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2019-19330
redhat medium — https://access.redhat.com/security/cve/CVE-2019-19330
suse medium CVE-2019-19330 severity moderate: SUSE including 2 source package names (haproxy, haproxy-1.8.23-3.el8), 18 product×package rows across 18 product lines (HPE Helion OpenStack 8, HPE Helion OpenStack Cloud 8, … (18 product lines)): Known Not Affected 17, Fixed 1. https://www.suse.com/security/cve/CVE-2019-19330/
ubuntu medium CVE-2019-19330 medium priority: Ubuntu including 1 source packages (haproxy), 6 status rows across 6 suites (bionic, disco, eoan, trusty, upstream, xenial): released 4, DNE 1, not-affected 1. https://ubuntu.com/security/CVE-2019-19330

Affected software / configurations for CVE-2019-19330

Vendor Product Version Raw CPE
haproxy haproxy < 2.0.10 cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.04 cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*
canonical ubuntu_linux 19.10 cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2019-19330

cvelogic Threat Intelligence