Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | haproxy | 2.0.10-1 | — |
| Debian 13 | haproxy | 2.0.10-1 | — |
| Debian 12 | haproxy | 2.0.10-1 | — |
| Debian 10 | haproxy | 1.8.19-1+deb10u1 | DSA-4577-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | haproxy | 1.8.8-1ubuntu0.9 | USN-4212-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | haproxy | 1.8.23-3.el8 | RHSA-2020:1725 |
| RHEL 3 | rh-haproxy18-haproxy +1 | 1.8.24-2.el7 | RHSA-2020:2265 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat OpenShift 4 | haproxy +1 | 2.0.13-3.el7 | RHSA-2020:1936 |
| Red Hat OpenShift 3 | haproxy +1 | 1.8.23-3.el7 | RHSA-2020:1287 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.9 | haproxy | 1.8.23-r0 | — |
| Alpine v3.8 | haproxy | 1.8.23 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | haproxy | 1.8.23-3.el8 | ELSA-2020-1725 |
Advisories 8
- WID-SEC-2024-0054 IBM Security Verify Access: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 16, 2026
- RHSA-2020:2265 Red Hat Security Advisory: rh-haproxy18-haproxy security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2020:1725 Red Hat Security Advisory: haproxy security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2020:1936 Red Hat Security Advisory: OpenShift Container Platform 4.4.3 haproxy security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2020:1287 Red Hat Security Advisory: OpenShift Container Platform 3.11 security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-4577-1 haproxy - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4212-1 haproxy vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026
- ELSA-2020-1725 Moderate: haproxy security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 5, 2020
References
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=54f53ef7ce4102be596130b44c768d1818570344
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=146f53ae7e97dbfe496d0445c2802dd0a30b0878
- https://git.haproxy.org/?p=haproxy-2.0.git%3Ba=commit%3Bh=ac198b92d461515551b95daae20954b3053ce87e
- https://tools.ietf.org/html/rfc7540#section-10.3
- DSA-4577 vendor-advisory
- 20191128 [SECURITY] [DSA 4577-1] haproxy security update mailing-list
- USN-4212-1 vendor-advisory
- GLSA-202004-01 vendor-advisory