HAProxy known bugs for version v2.6.33 (maintenance branch 2.6) :  57 

This version (2.6.33) is a release belonging to maintenance branch 2.6 whose latest version is 2.6.35. 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
2026-10-142.6.35 ⇐ last
2026-09-242.6.34 
2026-08-272.6.33 ⇐ yours
2026-07-292.6.32 
2026-07-032.6.31 
2026-06-262.6.30 
2026-05-112.6.29 
2026-05-062.6.28 
2026-04-302.6.27 
2026-04-232.6.26 
2026-03-202.6.25 
2026-03-092.6.24 
2025-10-032.6.23 
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 

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

These fixes have already been queued for a more recent 2.6 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
57 0 3 19 35

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

Merge dateSubject - Severity (minor, medium, major, critical)
2026-10-14BUG/MAJOR: h1-htx: report an error on a too long chunk-size line
2026-10-14BUG/MAJOR: mux-h2: properly handle short reads on PING frames
2026-10-12BUG/MEDIUM: mux-h1: only accept the H2 preface on the first request
2026-10-12BUG/MINOR: http-fetch: don't report pseudo-headers in TCP mode
2026-10-12BUG/MEDIUM: mux-h1: don't pass an upgraded connection to traces in h1s_destroy()
2026-10-12BUG/MEDIUM: mux-h2: don't return a freed tasklet from h2_deferred_shut()
2026-10-12BUG/MINOR: spoe: Fix the message list splice with an empty list
2026-10-12BUG/MINOR: cfgparse-listen: properly reject extra args in a backend section
2026-10-12BUG/MINOR: cfgparse-listen: update err_code for fatal error on proxy directive
2026-10-12BUG/MINOR: cfgparse-listen: fix the argument checked by "email-alert"
2026-10-12BUG/MINOR: cfgparse-listen: release the previous description of the proxy
2026-10-12BUG/MINOR: cfgparse-global: add missing calloc() check for the global description
2026-10-12BUG/MINOR: cfgparse-global: add missing gotos to error label in max-spread-checks
2026-10-12BUG/MINOR: mux_quic: extend FINAL_SIZE_ERROR detection on stream
2026-10-12BUG/MINOR: server: fix "del server" description
2026-10-12BUG/MINOR: sample: return the decoded JWT part when no path is given
2026-10-12BUG/MEDIUM: tcpcheck: do not run a regex on an unallocated buffer
2026-10-12BUG/MINOR: http-fetch: do not count Set-Cookie attributes as cookies
2026-10-12BUG/MINOR: payload: always report a boolean from req.ssl_ec_ext
2026-10-12BUG/MINOR: stick-table: do not count the lookup itself in table_trackers()
2026-10-12BUG/MINOR: http-ana: return a 502 when checkcache blocks a response
2026-10-12BUG/MINOR: sample: zero-pad the fractional part emitted by http_date()
2026-10-12BUG/MINOR: http: do not consume the delimiter of a truncated q-factor
2026-10-12BUG/MEDIUM: pattern: don't dereference static_pattern's data when not filling it
2026-10-12BUG/MEDIUM: stick-table: restrict key sizes to what fits in a buffer
2026-10-12BUG/MINOR: flt-http-comp: Rely on htx_set_eom() to restore EOM flag
2026-10-12BUG/MEDIUM: flt-http-comp: Block HTX_FL_EOM flag till the end of compression
2026-10-12BUG/MEDIUM: sink: reconnect attempt not working after session lasted more than ~25 days
2026-09-24BUG/MEDIUM: mux_quic: activate timeout on FE init
2026-09-24BUG/MINOR: http-ana: restore the transaction status after early hints
2026-09-24BUG/MINOR: tcpcheck: refresh the start-line after updating the authority
2026-09-24BUG/MINOR: http-fetch: fix the space check of http_auth_bearer()
2026-09-24BUG/MINOR: http-fetch: http_auth_bearer() must not match a missing header
2026-09-24BUG/MEDIUM: tcp-rules: ignore "capture len" rules evaluated from a backend
2026-09-24BUG/MEDIUM: http-act: ignore "capture len" rules evaluated from a backend
2026-09-24BUG/MEDIUM: http-htx: don't build the new authority in a rotating trash chunk
2026-09-24BUG/MINOR: http-client: Convert server timeout ticks when setting it
2026-09-21BUG/MINOR: hlua: release private Lua rule data on teardown
2026-09-21BUG/MAJOR: htx: Check the header/trailer length limits when one is updated
2026-09-18BUG/MEDIUM: limits: properly account for global.maxpipes in compute_ideal_maxconn()
2026-09-18BUG/MEDIUM: htx: Reserve a block descriptor for zero-sized blocks
2026-09-18BUG/MINOR: sample: reject a \0 byte in url_dec, json_query and jwt_*_query
2026-09-18BUG/MINOR: ssl: Fix leak of ca_list in cafile_entry
2026-09-18BUG/MEDIUM: http_act: fix normalize-uri normalizer selection with a condition
2026-09-18BUG/MEDIUM: map: do not overwrite the fetch context in pat_match_regm()
2026-09-18BUG/MINOR: ssl: don't pass the address of a size_t as an int* to OpenSSL
2026-09-18BUG/MINOR: h3: only increment frame type counter on new header
2026-09-18BUG/MINOR: h3: handle empty HEADERS frame as specified
2026-09-18BUG/MEDIUM: h3: do not block FIN on empty DATA frame
2026-09-18BUG/MINOR: hlua: Always return nil if there is no data to dup for HTTP messages
2026-09-18BUG/MEDIUM: hlua: Never release a cosocket applet from the GC
2026-09-18BUG/MINOR: qpack: accept a Required Insert Count which cannot be reached
2026-09-18BUG/MINOR: qpack: encoder and decoder stream data is never consumed
2026-09-18BUG/MINOR: resolvers: classify empty truncated responses
2026-09-18BUG/MINOR: quic: late packets of the first key phase are dropped
2026-09-18BUG/MEDIUM: quic: crash on key update phase change after a failed one
2026-09-18BUG/MINOR: payload: bound ClientHello extension lists by the extension length

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