A flaw was found in HAProxy before 2.0.6. In legacy mode, messages featuring a transfer-encoding header missing the "chunked" value were not being correctly rejected. The impact was limited but if combined with the "http-reuse always" setting, it could be used to help construct an HTTP request smuggling attack against a vulnerable component employing a lenient parser that would ignore the content-length header as soon as it saw a transfer-encoding one (even if not entirely valid according to the specification).
CVE-2019-18277
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 54EG Risk 54/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation40% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 10%
- EPSS %ILE
- 95th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (EG-KEV: elevated) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 23, 2019
Last Modified
November 21, 2024
References (14)
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2019-12/msg00016.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2019-12/msg00019.html
- cve@mitrehttps://git.haproxy.org/?p=haproxy-2.0.git%3Ba=commit%3Bh=196a7df44d8129d1adc795da020b722614d6a581
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2022/05/msg00045.html
- cve@mitrehttps://nathandavison.com/blog/haproxy-http-request-smuggling
- cve@mitrehttps://usn.ubuntu.com/4174-1/
- cve@mitrehttps://www.mail-archive.com/haproxy%40formilux.org/msg34926.html
- af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00016.html
- af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00019.html
- af854a3a-2127-422b-91ae-364da2661108https://git.haproxy.org/?p=haproxy-2.0.git%3Ba=commit%3Bh=196a7df44d8129d1adc795da020b722614d6a581
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2022/05/msg00045.html
- af854a3a-2127-422b-91ae-364da2661108https://nathandavison.com/blog/haproxy-http-request-smuggling
- af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/4174-1/
- af854a3a-2127-422b-91ae-364da2661108https://www.mail-archive.com/haproxy%40formilux.org/msg34926.html
Vendor Advisories for CVE-2019-18277(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(5)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | vim-haproxy (1.8.19-1ubuntu1.2) @ disco | 2026-05-27 | ubuntu |
| redhat | rh-haproxy18-haproxy-0:1.8.24-2.el7 | 2020-05-26 | redhat |
| redhat | haproxy-0:2.0.13-3.el7 | 2020-05-04 | redhat |
| redhat | haproxy-0:1.8.23-3.el8 | 2020-04-28 | redhat |
| redhat | haproxy-0:1.8.23-3.el7 | 2020-04-07 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(5 across 5 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| haproxy | — |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| haproxy | — |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| haproxy | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| haproxy | — |
| — |
Debian:9(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| haproxy | 1.7.5-2 |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(3)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 6× in last 7d / 26× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 154 total refreshes for this CVE.
- 2026-10-09 20:03 UTCEPSS rescore
- 2026-10-08 16:37 UTCEPSS rescore
- 2026-10-07 23:43 UTCEPSS rescore
- 2026-10-06 15:12 UTCEPSS rescore
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- 2026-10-03 14:22 UTCEPSS rescore
- 2026-09-30 14:59 UTCEPSS rescore
- 2026-09-30 10:14 UTCEG score recompute
- 2026-09-28 13:46 UTCEPSS rescore
- 2026-09-27 17:13 UTCOSV refresh
- 2026-09-27 13:40 UTCEPSS rescore
- 2026-09-26 15:54 UTCEPSS rescore
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- 2026-09-26 00:20 UTCEPSS rescore
- 2026-09-24 13:59 UTCEPSS rescore
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- 2026-09-15 03:05 UTCEPSS rescore
- 2026-09-12 14:56 UTCEPSS rescore
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- 2026-09-11 09:32 UTCEPSS rescore
- 2026-09-08 01:40 UTCOSV refresh
- 2026-09-07 15:57 UTCEPSS rescore
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- 2026-09-05 15:24 UTCEPSS rescore
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- 2026-08-30 19:13 UTCEPSS rescore
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- 2026-08-27 14:21 UTCEPSS rescore
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- 2026-08-21 23:45 UTCEPSS rescore
- 2026-08-21 11:44 UTCOSV refresh
- 2026-08-20 22:51 UTCEPSS rescore
- 2026-08-19 17:00 UTCEPSS rescore
- 2026-08-18 13:44 UTCEPSS rescore
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- 2026-08-15 01:26 UTCEPSS rescore
- 2026-08-12 13:47 UTCEPSS rescore
- 2026-08-09 13:43 UTCEPSS rescore
- 2026-08-08 16:33 UTCEPSS rescore
- 2026-08-07 16:23 UTCEPSS rescore
- 2026-08-06 13:43 UTCEPSS rescore
- 2026-08-05 23:24 UTCOSV refresh
- 2026-08-05 19:13 UTCEPSS rescore
- 2026-08-04 15:05 UTCEPSS rescore
- 2026-08-02 02:23 UTCEPSS rescore
- 2026-08-01 04:12 UTCEPSS rescore
- 2026-07-30 16:24 UTCEPSS rescore
- 2026-07-30 01:27 UTCEPSS rescore
- 2026-07-28 15:32 UTCEPSS rescore
- 2026-07-26 14:51 UTCEPSS rescore
- 2026-07-25 14:14 UTCEPSS rescore
- 2026-07-24 14:14 UTCEPSS rescore
- 2026-07-24 14:14 UTCEPSS rescore
- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 01:42 UTCEG score recompute
- 2026-07-22 22:22 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 03:16 UTCOSV refresh
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-18 10:01 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-12 05:43 UTCEPSS rescore
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- 2026-07-11 08:24 UTCEPSS rescore
- 2026-07-09 19:06 UTCEPSS rescore
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- 2026-07-07 13:43 UTCEPSS rescore
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- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-05 02:27 UTCEPSS rescore
- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-02 18:05 UTCOSV refresh
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:9:haproxy · Debian:11:haproxy
- CVE-2018-20103EG 7.5EPSS p94HIGH
- CVE-2018-20102EG 7.5EPSS p91HIGH
- CVE-2019-19330EG 9.8EPSS p90CRITICAL
- CVE-2026-55203EG 9.1CRITICAL
- CVE-2023-25725EG 9.1EPSS p93CRITICAL
- CVE-2023-44487NVD 7.5EG 9.0 KEVEPSS p100CRITICAL
- CVE-2020-11100EG 8.9EPSS p99HIGH
- CVE-2021-40346NVD 7.5EG 8.3EPSS p99HIGH
- CVE-2023-45539EG 8.2HIGH
- CVE-2016-5360NVD 7.5EG 7.8EPSS p99HIGH
Same vendor
2 shownredhat:RHSA-2020:1287
Same CWE
10 shownCWE-444
Frequently asked(5)
What is CVE-2019-18277?
When was CVE-2019-18277 disclosed?
Is CVE-2019-18277 actively exploited?
What is the CVSS score of CVE-2019-18277?
How do I remediate CVE-2019-18277?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2019-18277
Is Your Infrastructure Affected by CVE-2019-18277?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.