How severe is CVE-2018-20615?

CVE-2018-20615 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-20615 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20615?

CVE-2018-20615 primarily affects Haproxy. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-20615?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-20615 published?

CVE-2018-20615 was published on 2019-03-21 and last updated on 2026-06-17.

CVE-2018-20615

CVE-2018-20615 is a high-severity vulnerability in Haproxy with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Haproxy
Published: 2019-03-21
Last modified: 2026-06-17

Description

An out-of-bounds read issue was discovered in the HTTP/2 protocol decoder in HAProxy 1.8.x and 1.9.x through 1.9.0 which can result in a crash. The processing of the PRIORITY flag in a HEADERS frame requires 5 extra bytes, and while these bytes are skipped, the total frame length was not re-checked to make sure they were present in the frame.

Frequently asked questions

What is CVE-2018-20615?: An out-of-bounds read issue was discovered in the HTTP/2 protocol decoder in HAProxy 1.8.x and 1.9.x through 1.9.0 which can result in a crash. The processing of the PRIORITY flag in a HEADERS frame requires 5 extra bytes, and while these bytes are skipped, the total frame length was not re-checked to make sure they were present in the frame.
How severe is CVE-2018-20615?: CVE-2018-20615 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-20615 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20615?: CVE-2018-20615 primarily affects Haproxy. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-20615?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-20615 published?: CVE-2018-20615 was published on 2019-03-21 and last updated on 2026-06-17.

References

Affected products (23)

cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:-:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev0:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev1:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev10:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev11:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev2:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev3:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev4:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev5:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev6:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev7:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev8:*:*:*:*:*:*
cpe:2.3:a:haproxy:haproxy:1.9.0:dev9:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.5:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.6:*:*:*:*:*:*:*

More vulnerabilities in Haproxy

CVE-2019-19330 — Critical (CVSS 9.8): The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (CR, ASCII…
CVE-2023-25725 — Critical (CVSS 9.1): HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some…
CVE-2020-11100 — High (CVSS 8.8): In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can…
CVE-2023-45539 — High (CVSS 8.2): HAProxy before 2.8.2 accepts # as part of the URI component, which might allow remote attackers to obtain sensitive…
CVE-2026-55204 — High (CVSS 7.5): HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in…
CVE-2026-55203 — High (CVSS 7.5): HAProxy through 3.4.0, fixed in commit 5985276, contains an integer overflow vulnerability in the fcgi_conn structure's…

All CVEs affecting Haproxy →

Other CWE-125 (Out-of-bounds Read) vulnerabilities

CVE-2026-24826 — Critical (CVSS 10.0): Out-of-bounds Write, Divide By Zero, NULL Pointer Dereference, Use of Uninitialized Resource, Out-of-bounds Read,…
CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

Browse all CWE-125 (Out-of-bounds Read) vulnerabilities →