HAProxy known bugs for maintenance branch 2.6 :  3 

This is maintenance branch 2.6 whose latest version is 2.6.23. 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 2.6 version other than 2.6.23, you're running with known bugs.

Quick links

Versions available in this branch

This branch contains the following releases :

DateVersionComment
2025-10-032.6.23 ⇐ last
2025-04-222.6.22 
2025-01-292.6.21 
2024-11-082.6.20 
2024-09-192.6.19 
2024-06-182.6.18 
2024-04-052.6.17 
2023-12-132.6.16 
2023-08-092.6.15 
2023-06-092.6.14 
2023-05-022.6.13 
2023-03-282.6.12 
2023-03-172.6.11 
2023-03-102.6.10 
2023-02-142.6.9 
2023-01-242.6.8 
2022-12-022.6.7 
2022-09-222.6.6 
2022-09-032.6.5 
2022-08-222.6.4 
2022-08-192.6.3 
2022-07-222.6.2 
2022-06-212.6.1 
2022-05-312.6.0 

Fixes for known bugs pending in this branch since the last release (2.6.23)

These fixes have already been queued for the next 2.6 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 :

Total known bugs in the latest version of this branch by category :

TotalCRITICALMAJORMEDIUMMINOR
3 0 0 1 2

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

Merge dateSubject - Severity (minor, medium, major, critical)
2025-10-14BUG/MINOR: sink: retry attempt for sft server may never occur
2025-10-10BUG/MINOR: ssl: always clear the remains of the first hello for the second one
2025-10-10BUG/MEDIUM: ssl: take care of second client hello

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.

DateSubject
2025-10-24BUG/MEDIUM: mt_list: Use atomic operations to prevent compiler optims
2025-10-24BUG/MINOR: stick-tables: properly index string-type keys
2025-10-24BUG/MAJOR: stats-file: ensure shm_stats_file_object struct mapping consistency (2nd attempt)
2025-10-24Revert "BUG/MAJOR: stats-file: ensure shm_stats_file_object struct mapping consistency"
2025-10-24BUG/MEDIUM: applet: Improve again spinning loops detection with the new API
2025-10-23BUG/MINOR: quic: rename and duplicate stream settings
2025-10-23BUG/MINOR: quic: split option for congestion max window size
2025-10-23BUG/MINOR: quic: split max-idle-timeout option for FE/BE usage
2025-10-23BUG/MEDIUM: mt_lists: Avoid el->prev = el->next = el
2025-10-23BUG/MEDIUM: stick-tables: Don't loop if there's nothing left
2025-10-23BUG/MEDIUM: build: limit excessive and counter-productive gcc-15 vectorization
2025-10-22BUG/MAJOR: stats-file: ensure shm_stats_file_object struct mapping consistency
2025-10-22BUG/MAJOR: quic: use ncbmbuf for CRYPTO handling
2025-10-22BUG/MAJOR: pools: fix default pool alignment
2025-10-21BUG/MEDIUM: h3: properly encode response after interim one in same buf
2025-10-21BUG/MEDIUM: h1-htx: Don't set HTX_FL_EOM flag on 1xx informational messages
2025-10-20BUG/MEDIUM: cli: also free the trash chunk on the error path
2025-10-20BUG/MINOR: quic-be: unchecked connections during handshakes
2025-10-19BUG/MEDIUM: mt_list: Make sure not to unlock the element twice
2025-10-17BUG/MEDIUM: threads/config: drop absent threads from thread groups
2025-10-17BUG/MINOR: quic: SSL counters not handled
2025-10-17BUG/MAJOR: quic: do not reset QUIC backends fds in closing state
2025-10-17BUG/MAJOR: quic: uninitialized quic_conn_closed struct members
2025-10-17BUG/MINOR: quic: check applet_putchk() for 'show quic' first line
2025-10-16BUG/MEDIUM: stick-tables: Don't forget to dec count on failure.
2025-10-16BUG/MAJOR: lb-chash: fix key calculation when using default hash-key id
2025-10-16BUG/MINOR: pools: don't report "limited to the first X entries" by default
2025-10-16BUG/MEDIUM: pools: fix crash on filtered "show pools" output

Back to the list of branches and versions
Back to the HAProxy page