Redis 8.8-RC1 Release Candidate

This is the first Release Candidate of Redis 8.8 in Redis Open Source.

Release Candidates are feature-complete pre-releases. Pre-releases are not suitable for production use.

Headlines:

Redis 8.8 introduces new features and performance improvements.

Operating systems we test Redis 8.8 on

• Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat), 26.04 (Resolute Raccoon)
• Rocky Linux 8.10, 9.7, 10.1
• AlmaLinux 8.10, 9.7, 10.1
• Debian 12.13 (Bookworm), Debian 13.4 (Trixie)
• Alpine 3.23
• macOS 14.8.4 (Sonoma), 15.7.4 (Sequoia), 26.3 (Tahoe) - for both Intel and ARM

Security fixes (compared to 8.8-M03)

• (CVE-2026-23479) Use-After-Free in unblock client flow may lead to Remote Code Execution.
• (CVE-2026-25243) Invalid memory access in RESTORE may lead to Remote Code Execution
• (CVE-2026-23631) Lua Use-After-Free may lead to remote code execution
• (CVE-2026-25588) Invalid memory access in RESTORE may lead to Remote Code Execution (Time Series)
• (CVE-2026-25589) Invalid memory access in RESTORE may lead to Remote Code Execution (Probabilistic)

New Features (compared to 8.8-M03)

• #15162 New data structure: Array (@antirez)
• #15045 INCREX: a window counter rate limiter combining INCR,INCRBY,INCRBYFLOAT, bounds, and expiration (@raffertyyu + Redis team)
• In group sorting new reducer, allowing unwind grouped documents (after GROUPBY) and sort them

Removed Features (compared to 8.8-M03)

• #15191 Remove GCRA rate limiter

Bug fixes (compared to 8.8-M03)

• SUBSCRIBE, PSUBSCRIBE, SSUBSCRIBE: crash on OOM (RED-167788)
• CONFIG SET: some settings allow invalid characters (RED-167787)
• SCRIPT DEBUG: potential crash on scripts (RED-175507)
• VADD: crash or buffer overflow on large REDUCE value (RED-170921)
• VSET: crash on huge allocations (MOD-12678)
• #15188 cluster-announce-ip rejecting hostnames (regression)
• #15095 Double free when loading streams with duplicate consumer PEL entries
• #15124 Issues processing corrupt Streams RDB data
• #15111 fast_float_strtod rounding mismatch
• #15190 vecClear reset the logical size without releasing element ownership
• #15163 MULTI queue memory incorrect memory accounting
• #15094 Cluster crash when CLIENT KILL unsubscribes SSUBSCRIBE client inside EXEC
• #15151 Listpack backlength encoding thresholds off-by-one
• #15115 Under-copy in the Lua debugger
• #14970 Sentinel config injection via SENTINEL SET
• #14934 Client output buffer memory tracking not accounting for copy-avoided bulk string references
• RediSearch/RediSearch#9182 FT.PROFILE HYBRID returns an empty reply (MOD-14778)
• RediSearch/RediSearch#9079 FT.SPELLCHECK treats PARAMS placeholders as literal terms instead of resolving them (MOD-10596)
• RediSearch/RediSearch#9047 FT.PROFILE output is inconsistent when a profiled value is missing (MOD-10560)
• RediSearch/RediSearch#9078 FT.CREATE now rejects schema definitions with invalid option combinations at creation time (MOD-14655)
• RediSearch/RediSearch#9012 PERSIST and HPERSIST notifications are not reflected in index expiration tracking (MOD-14800)
• RediSearch/RediSearch#9066 Race condition in FT.HYBRID causes intermittent failures under concurrent hybrid query load (MOD-14732)
• RediSearch/RediSearch#9163 Crash on FT.SEARCH when topology validation fails (for example, some nodes unreachable) (MOD-14475)
• RediSearch/RediSearch#9031, RediSearch/RediSearch#9473 Coordinator deadlock under mixed FT.SEARCH and FT.AGGREGATE load (MOD-14268)
• RediSearch/RediSearch#9028 Memory leak when FT.DROPINDEX runs concurrently with in-flight hybrid queries (MOD-14135)
• RediSearch/RediSearch#9310, RediSearch/RediSearch#9350 FT.CURSOR READ timeout and ON_TIMEOUT FAIL not enforced on coordinator and shard (MOD-14284, MOD-14998)
• RediSearch/RediSearch#9425 Cursors not cleaned up after MAXIDLE, causing resource exhaustion (MOD-6430)
• RediSearch/RediSearch#9234, RediSearch/RediSearch#9404 Coordinator RETURN_STRICT returns wrong data on partial results, including SORTBY pipeline (MOD-13617)
• RediSearch/RediSearch#9382 MAXPREFIXEXPANSION warnings not propagated to clients in cluster mode (MOD-13804)
• RediSearch/RediSearch#9218 Search commands fail when no worker thread is available instead of falling back to main thread (MOD-14921)
• RediSearch/RediSearch#9448 RDB load missing validation of FT.CREATE arguments, allowing corrupt index state on load (MOD-13118)
• RediSearch/RediSearch#9377 Use-after-move in Indexer_Process causes crash during indexing (MOD-14980)
• RediSearch/RediSearch#9408 Deadlock between background query and main-thread writer (MOD-15364)
• RediSearch/RediSearch#9114 FT.PROFILE prints output using wrong iterator type (MOD-14678)
• RediSearch/RediSearch#9421 Confusing error returned when DEBUG_PARAMS_COUNT is zero (MOD-15118)
• RediSearch/RediSearch#9045 Stack-smashing error in coordinator code path (MOD-14649)
• RedisJSON/RedisJSON#1554 Trailing chars are ignored (MOD-7266); Fixes RedisJSON/RedisJSON#976
• RedisJSON/RedisJSON#1543 Wrong mutation ordering for array commands with recursive paths (MOD-6722)
• RedisJSON/RedisJSON#1542 JSONPath evaluation issues (MOD-14664); Fixes RedisJSON/RedisJSON#968 (MOD-7264), RedisJSON/RedisJSON#962 (MOD-7272), RedisJSON/RedisJSON#963 (MOD-7270), RedisJSON/RedisJSON#1089 (MOD-7268)
• RedisTimeSeries/RedisTimeSeries#2003 Potential crash on disconnections and TLS failures (MOD-14850)
• RedisTimeSeries/RedisTimeSeries#2013 count, countNaN, countAll reducers return NaN when all values are NaN (MOD-14420)

Performance and resource utilization improvements (compared to 8.8-M03)

• #15049 Hyperloglog: 4 independent accumulators that are merged at the end
• #15133 Batched prefetch for MGET and MSET
• #14988 Batched prefetch for HGETALL on hashtable-encoded hashes
• #15071 Pass size hint to jemalloc for faster deallocation
• #15096 Reduces allocator and accounting overhead by adding compile-time jemalloc tuning
• RediSearch/RediSearch#9197 Vector index hot path (HNSW and brute-force) devirtualized, reducing per-query latency (MOD-14916)
• RediSearch/RediSearch#9262, RediSearch/RediSearch#9476 Inline LSE atomics enabled on AArch64, improving atomic operation throughput on ARM64 (MOD-14916, MOD-15419)
• RediSearch/RediSearch#9293 Expiration handling overhead reduced when many keys expire simultaneously (MOD-14916)
• RediSearch/RediSearch#9017 LTO (link-time optimization) enabled for x86_64 release builds (MOD-14700)
• RediSearch/RediSearch#8765 Shard-level timeout adjusted to coordinator dispatch time for more accurate accounting (MOD-13189)
• RediSearch/RediSearch#8790, RediSearch/RediSearch#8900, RediSearch/RediSearch#8827, RediSearch/RediSearch#8971, RediSearch/RediSearch#8966, RediSearch/RediSearch#8762, RediSearch/RediSearch#8678, RediSearch/RediSearch#8915, RediSearch/RediSearch#8653, RediSearch/RediSearch#9085, RediSearch/RediSearch#8751, RediSearch/RediSearch#8692, RediSearch/RediSearch#9224 Iterators ported to Rust, reducing FFI overhead
• RediSearch/RediSearch#9500 numRecords no longer updated for vector fields, removing unnecessary write overhead on ingest (MOD-15487)
• VecSim SVS thread pool integrated with the worker pool for better thread utilization (MOD-9881)

Configuration parameters

• #15182 Slowlog entry truncation limits:
  • slowlog-entry-max-argc: maximum number of command arguments kept in a slowlog entry
  • slowlog-entry-max-string-len: maximum length of a command argument in a slowlog entry
• RediSearch/RediSearch#8876, RediSearch/RediSearch#8960 Default maximum worker threads value updated; MAX_WORKER_THREADS is now a string config (MOD-14486, MOD-14763)

Metrics (compared to 8.8-M03)

• RediSearch/RediSearch#8210, RediSearch/RediSearch#8231 FT.PROFILE: added queue time tracking (MOD-13602)

CLI tools

• #15150 Memory leak on malformed legacy help entry in redis-cli