HAProxy known bugs for version v3.4.0 (maintenance branch 3.4) :  47 

This version (3.4.0) 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.

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Other versions in the same branch

This branch contains the following releases :

DateVersionComment
2026-07-033.4.2 ⇐ last
2026-06-253.4.1 
2026-06-033.4.0 ⇐ yours

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 :

Total known bugs in this version by category :

TotalCRITICALMAJORMEDIUMMINOR
47 0 1 25 21

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

Merge dateSubject - Severity (minor, medium, major, critical)
2026-07-02BUG/MINOR: http-htx: Don't by-pass HTX API when merging cookie values
2026-07-02BUG/MINOR: mux-quic: Fix handling EOM after in qcs_http_rcv_buf()
2026-07-02BUG/MAJOR: htx: Don't swap buffers for empty HTX message with an error
2026-07-02BUG/MINOR: tools: fix invalid character detection in strl2ic()
2026-07-02BUG/MINOR: init: fix default global settings being overwritten by -G
2026-07-02BUG/MEDIUM: servers: Use a refcount for port_range and free it properly
2026-07-02BUG/MINOR: sample: set SMP_F_CONST on srv_name fetch
2026-07-02BUG/MEDIUM: server: initialise agent.health in srv_settings_init()
2026-07-02BUG/MINOR: hq-interop: support transcoding of absolute URI
2026-07-02BUG/MINOR: hq-interop: fix transcoding of wrapping response buffer
2026-07-02BUG/MEDIUM: mux_quic: fix memory leak of rx app_buf on stream free
2026-06-25BUG/MEDIUM: mux-quic: Drain the given amount of data in qcs_http_reset_buf()
2026-06-25BUG/MEDIUM: mux-spop: Truly drain outgoing data when the stream is closed
2026-06-25BUG/MEDIUM: mux-h2: Truly drain outgoing HTX data when the stream is closed
2026-06-25BUG/MEDIUM: mux-fcgi: Truly drain outgoing HTX data when the stream is closed
2026-06-25BUG/MEDIUM: h3: increment unknown request payload length
2026-06-25BUG/MINOR: hq-interop: support response buffer wrapping
2026-06-25BUG/MINOR: hq-interop: support full demux buf on large response
2026-06-25BUG/MEDIUM: hlua: Properly report EOS when http applet exits
2026-06-25BUG/MINOR: hq-interop: prevent reset if missing content-length
2026-06-25BUG/MINOR: hq-interop: reject too big content
2026-06-18BUG/MEDIUM: mux-fcgi: fix uint16_t overflow in drl += drp
2026-06-18BUG/MEDIUM: http-act: Make a copy of the sample expr in (set/add)-headers-bin
2026-06-18BUG/MEDIUM: mux_quic: fix freeze transfer after QCS rxbuf realign
2026-06-18BUG/MINOR: hpack-tbl: add missing NULL check after hpack_dht_defrag()
2026-06-18BUG/MEDIUM: ssl: Don't free the early data buffer too early
2026-06-18BUG/MINOR: quic: fix rxbuf settings on backend side
2026-06-18BUG/MINOR: mux-h1: Properly resolve file path for 'h1-case-adjust-file'
2026-06-18BUG/MEDIUM: http-ana: Don't ignore L7 retry errors
2026-06-18BUG/MINOR: http-ana: Remove a debugging memset on redirect
2026-06-18BUG/MINOR: server: fix add server with consistent hash balancing
2026-06-18BUG/MEDIUM: h3: Properly handle PUSH_PROMISE on backend connections
2026-06-18BUG/MINOR: cpu-topo: use ha_diag_notice() to report thread creations
2026-06-18BUG/MEDIUM: ktls: defer enabling TLS ULP on a socket until connected
2026-06-18BUG/MEDIUM: acme: stuck ACME task when authz is already "valid"
2026-06-18BUG/MINOR: quic: fix Initial length value in sent packets
2026-06-09BUG/MEDIUM: checks: Dequeue checks on purge
2026-06-09BUG/MINOR: acl: report "ACL" not "map" in ACL ID lookup failures
2026-06-09BUG/MEDIUM: xprt_qmux: implement ->get_ssl_sock_ctx() to get the SSL laye
2026-06-09BUG/MEDIUM: threads: Fiw build when using no thread
2026-06-09BUG/MEDIUM: regex: initialize the match array earlier during boot
2026-06-09BUG/MINOR: tcpcheck: Override external check if healthcheck section is set
2026-06-09BUG/MINOR: mux_quic: do not interrupt recv on error/incomplete data
2026-06-09BUG/MEDIUM: mux_quic: prevent risk of infinite loop on recv
2026-06-05BUG/MEDIUM: server/checks: Support healtcheck keyword on default-server lines
2026-06-05BUG/MEDIUM: check: Ignore small-buffer option when starting an external check
2026-06-05BUG/MEDIUM: check: Skip tcpcheck post-config for external checks

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