HAProxy known bugs for maintenance branch 3.1 : 22

This is maintenance branch 3.1 whose latest version is 3.1.9. 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. In short, if you are running any 3.1 version other than 3.1.9, you're running with known bugs.

Quick links

full changelog for 3.1 : here
browse history for 3.1 : here

Versions available in this branch

This branch contains the following releases :

Date Version Comment

2025-10-03 3.1.9 ⇐ last

2025-06-02 3.1.8

2025-04-17 3.1.7

2025-03-20 3.1.6

2025-02-20 3.1.5

2025-02-19 3.1.4

2025-01-29 3.1.3

2025-01-08 3.1.2

2024-12-11 3.1.1

2024-11-26 3.1.0

Date	Version	Comment
2025-10-03	3.1.9	⇐ last
2025-06-02	3.1.8
2025-04-17	3.1.7
2025-03-20	3.1.6
2025-02-20	3.1.5
2025-02-19	3.1.4
2025-01-29	3.1.3
2025-01-08	3.1.2
2024-12-11	3.1.1
2024-11-26	3.1.0

Fixes for known bugs pending in this branch since the last release (3.1.9)

These fixes have already been queued for the next 3.1 release but no version was released with them yet. Note that fixes are backported several at a time from the development branch to maintenance branches, and the absence of a fix here doesn't mean none will be issued soon.

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 the latest version of this branch by category :

Total CRITICAL MAJOR MEDIUM MINOR

22 0 3 11 8

Total	CRITICAL	MAJOR	MEDIUM	MINOR
22	0	3	11	8

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

Merge date	Subject - Severity (minor, medium, major, critical)
2025-10-27	BUG/MEDIUM: cli: do not return ACKs one char at a time
2025-10-27	BUG/MEDIUM: mt_list: Use atomic operations to prevent compiler optims
2025-10-27	BUG/MINOR: stick-tables: properly index string-type keys
2025-10-27	BUG/MEDIUM: applet: Improve again spinning loops detection with the new API
2025-10-27	BUG/MEDIUM: mt_lists: Avoid el->prev = el->next = el
2025-10-27	BUG/MEDIUM: build: limit excessive and counter-productive gcc-15 vectorization
2025-10-27	BUG/MAJOR: quic: use ncbmbuf for CRYPTO handling
2025-10-27	BUG/MEDIUM: h3: properly encode response after interim one in same buf
2025-10-27	BUG/MAJOR: quic: uninitialized quic_conn_closed struct members
2025-10-27	BUG/MEDIUM: mt_list: Make sure not to unlock the element twice
2025-10-27	BUG/MEDIUM: threads/config: drop absent threads from thread groups
2025-10-27	BUG/MINOR: quic: check applet_putchk() for 'show quic' first line
2025-10-27	BUG/MEDIUM: stick-tables: Don't forget to dec count on failure.
2025-10-17	BUG/MINOR: quic: too short PADDING frame for too short packets
2025-10-16	BUG/MAJOR: lb-chash: fix key calculation when using default hash-key id
2025-10-16	BUG/MINOR: ssl: Free key_base from global_ssl structure during deinit
2025-10-16	BUG/MINOR: ssl: Free global_ssl structure contents during deinit
2025-10-14	BUG/MINOR: sink: retry attempt for sft server may never occur
2025-10-10	BUG/MEDIUM: apppet: Improve spinning loop detection with the new API
2025-10-10	BUG/MINOR: ssl: always clear the remains of the first hello for the second one
2025-10-10	BUG/MEDIUM: ssl: take care of second client hello
2025-10-10	BUG/MINOr: hlua: Fix receive from HTTP applet by properly accounting data

Known bugs fixed in the development branch after the last commit in this branch

It is important to understand that not all of these commits are necessarily relevant to this version, but clicking on them will show the bug description. All fixes are made first in the development branch and then backported to the maintenance branches. This ensures no fix is lost when upgrading. If a fix was marked for backporting to this branch and is not there yet, it's likely that it is still missing. Do not hesitate to ask on the haproxy mailing list if you feel like a fix has been skipped.

Date Subject

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