CVE-2020-11100
CVE-2020-11100 is a high-severity vulnerability in Haproxy with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 61% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- CVSS v2: 6.5
- EPSS exploit prediction: 61% (99th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Haproxy
- Published:
- Last modified:
Description
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 write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.
Frequently asked questions
- What is CVE-2020-11100?
- 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 write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.
- How severe is CVE-2020-11100?
- CVE-2020-11100 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-11100 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 61% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-11100?
- CVE-2020-11100 primarily affects Haproxy. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-11100?
- 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-2020-11100 published?
- CVE-2020-11100 was published on 2020-04-02 and last updated on 2026-06-17.
References
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00002.html
- http://packetstormsecurity.com/files/157323/haproxy-hpack-tbl.c-Out-Of-Bounds-Write.html
- http://www.haproxy.org
- https://bugzilla.redhat.com/show_bug.cgi?id=1819111
- https://bugzilla.suse.com/show_bug.cgi?id=1168023
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=5dfc5d5cd0d2128d77253ead3acf03a421ab5b88
- https://lists.debian.org/debian-security-announce/2020/msg00052.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/264C7UL3X7L7QE74ZJ557IOUFS3J4QQC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNW5RZLIX7LOXRLV7WMHX22CI43XSXKW/
- https://security.gentoo.org/glsa/202012-22
- https://usn.ubuntu.com/4321-1/
- https://www.debian.org/security/2020/dsa-4649
- https://www.haproxy.org/download/2.1/src/CHANGELOG
- https://www.mail-archive.com/haproxy%40formilux.org/msg36876.html
Affected products (9)
- cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
- cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*
- cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
- cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
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