HAProxy known bugs for version v3.4.1 (maintenance branch 3.4) : 11

This version (3.4.1) is a release belonging to maintenance branch 3.4 whose latest version is 3.4.2. If your version is not the last one in the maintenance branch, you are missing fixes for known bugs, and by not updating you are needlessly taking the responsibility for the risk of unexpected service outages and exposing your web site to possible security issues.

The HAProxy development team takes a great care of maintaining stable versions so that all users can apply bug fixes without having to take the risk of upgrading to a new branch. In turn users are expected to apply the fixes when the development team estimates that they were worth being backported to stable branches.

Quick links

full changelog for 3.4 : here
browse history for 3.4 : here

Other versions in the same branch

This branch contains the following releases :

Date Version Comment

2026-07-03 3.4.2 ⇐ last

2026-06-25 3.4.1 ⇐ yours

2026-06-03 3.4.0

Date	Version	Comment
2026-07-03	3.4.2	⇐ last
2026-06-25	3.4.1	⇐ yours
2026-06-03	3.4.0

Known bugs affecting this version, and already fixed in the maintenance branch

These fixes have already been queued for a more recent 3.4 version. Some of them might have already been released in a more recent version than yours, and other ones might still be pending in the maintenance branch for a future release. The list may be empty if you're already on the latest version and no new fix was backported.

Bugs are almost always tagged with a severity (some people forget the severity tag when the bug is minor). The following severities are used :

MINOR: the bug presents a limited impact and can easily be mitigated ; users rarely upgrade just for these ones ;
MEDIUM: the bug can cause some undesired behaviour and may require some tricky configuration changes to avoid hitting it ; users normally upgrade to get rid of them, or temporarily disable a functionality.
MAJOR: the bug affects short term reliability and cannot easily be worked around without a significant performance penalty or without a significant functional loss ; such bugs don't stay long in the queue without a release and users must plan an upgrade as soon as possible ;
CRITICAL: this one very rarely happens ; it indicates a short-term reliability or security issue for which there is no workaround. A release will be emitted for this fix even if it's alone and users are urged to upgrade immediately. Some distro maintainers might have been informed in advance in order to agree on a coordinated release date.

Total known bugs in this version by category :

Total CRITICAL MAJOR MEDIUM MINOR

11 0 1 3 7

Total	CRITICAL	MAJOR	MEDIUM	MINOR
11	0	1	3	7

Click on the subjects below to get the full description of the bug :

Merge date Subject - Severity (minor, medium, major, critical)

2026-07-02 BUG/MINOR: http-htx: Don't by-pass HTX API when merging cookie values

2026-07-02 BUG/MINOR: mux-quic: Fix handling EOM after in qcs_http_rcv_buf()

2026-07-02 BUG/MAJOR: htx: Don't swap buffers for empty HTX message with an error

2026-07-02 BUG/MINOR: tools: fix invalid character detection in strl2ic()

2026-07-02 BUG/MINOR: init: fix default global settings being overwritten by -G

2026-07-02 BUG/MEDIUM: servers: Use a refcount for port_range and free it properly

2026-07-02 BUG/MINOR: sample: set SMP_F_CONST on srv_name fetch

2026-07-02 BUG/MEDIUM: server: initialise agent.health in srv_settings_init()

2026-07-02 BUG/MINOR: hq-interop: support transcoding of absolute URI

2026-07-02 BUG/MINOR: hq-interop: fix transcoding of wrapping response buffer

2026-07-02 BUG/MEDIUM: mux_quic: fix memory leak of rx app_buf on stream free

Merge date	Subject - Severity (minor, medium, major, critical)
2026-07-02	BUG/MINOR: http-htx: Don't by-pass HTX API when merging cookie values
2026-07-02	BUG/MINOR: mux-quic: Fix handling EOM after in qcs_http_rcv_buf()
2026-07-02	BUG/MAJOR: htx: Don't swap buffers for empty HTX message with an error
2026-07-02	BUG/MINOR: tools: fix invalid character detection in strl2ic()
2026-07-02	BUG/MINOR: init: fix default global settings being overwritten by -G
2026-07-02	BUG/MEDIUM: servers: Use a refcount for port_range and free it properly
2026-07-02	BUG/MINOR: sample: set SMP_F_CONST on srv_name fetch
2026-07-02	BUG/MEDIUM: server: initialise agent.health in srv_settings_init()
2026-07-02	BUG/MINOR: hq-interop: support transcoding of absolute URI
2026-07-02	BUG/MINOR: hq-interop: fix transcoding of wrapping response buffer
2026-07-02	BUG/MEDIUM: mux_quic: fix memory leak of rx app_buf on stream free

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