Dev Builds » 20260819-1638

Use this dev build

NCM plays each Stockfish dev build 20,000 times against Stockfish 15. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.

Summary

Host Duration Avg Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo
ncm-dbt-01 06:48:30 584115 4008 1817 320 1871 +136.36 ± 4.37 0 16 515 1433 40 +320.49 ± 14.97
ncm-dbt-02 06:48:19 591277 3992 1795 299 1898 +136.87 ± 4.37 0 24 483 1458 31 +325.64 ± 15.5
ncm-dbt-03 06:48:12 576496 4000 1823 303 1874 +138.99 ± 4.32 0 11 500 1447 42 +329.46 ± 15.17
ncm-dbt-04 06:48:51 568123 4000 1775 292 1933 +135.25 ± 4.41 0 19 518 1424 39 +316.8 ± 14.93
ncm-dbt-05 06:47:48 605122 4000 1828 287 1885 +141.13 ± 4.37 0 17 470 1468 45 +336.46 ± 15.7
20000 9038 1501 9461 +137.72 ± 1.95 0 87 2486 7230 197 +325.67 ± 6.81

Test Detail

ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN
482966 ncm-dbt-01 582861 8 4 1 3 +136.8 ± 89.09 0 0 1 3 0 +337.69 ± 541.44
482965 ncm-dbt-02 592116 492 218 26 248 +143.17 ± 13.49 0 6 49 184 7 +339.66 ± 49.35
482964 ncm-dbt-04 568236 500 218 33 249 +134.95 ± 12.64 0 2 67 175 6 +312.48 ± 41.9
482963 ncm-dbt-05 602784 500 235 40 225 +143.07 ± 11.24 0 1 55 192 2 +356.21 ± 46.49
482962 ncm-dbt-03 578300 500 237 35 228 +148.85 ± 12.27 0 1 54 187 8 +359.68 ± 46.95
482961 ncm-dbt-01 584706 500 224 46 230 +129.35 ± 12.21 0 2 71 174 3 +301.33 ± 40.6
482960 ncm-dbt-02 590739 500 226 40 234 +135.76 ± 11.8 0 2 62 184 2 +327.18 ± 43.69
482959 ncm-dbt-04 568514 500 216 40 244 +127.76 ± 12.84 0 3 73 169 5 +290.66 ± 40.08
482958 ncm-dbt-03 574054 500 221 36 243 +134.95 ± 12.44 0 2 66 177 5 +315.35 ± 42.24
482957 ncm-dbt-05 600691 500 228 35 237 +141.44 ± 12.41 0 2 59 183 6 +336.46 ± 44.87
482956 ncm-dbt-01 584285 500 227 36 237 +139.81 ± 12.05 0 1 62 182 5 +333.32 ± 43.57
482955 ncm-dbt-02 591555 500 230 41 229 +138.18 ± 11.91 0 1 63 182 4 +330.23 ± 43.2
482954 ncm-dbt-04 566217 500 219 40 241 +130.14 ± 13.16 0 3 72 168 7 +293.29 ± 40.39
482953 ncm-dbt-03 578588 500 226 43 231 +133.34 ± 12.89 0 3 67 174 6 +306.84 ± 41.99
482952 ncm-dbt-01 585169 500 228 39 233 +138.18 ± 11.91 0 0 66 179 5 +327.17 ± 41.95
482951 ncm-dbt-05 605523 500 222 38 240 +134.15 ± 12.86 0 4 63 178 5 +312.48 ± 43.44
482950 ncm-dbt-04 567839 500 222 31 247 +139.81 ± 12.05 0 1 62 182 5 +333.32 ± 43.57
482949 ncm-dbt-02 592461 500 218 41 241 +128.55 ± 12.43 0 1 76 168 5 +293.29 ± 38.98
482948 ncm-dbt-01 586562 500 226 31 243 +143.07 ± 12.34 0 1 60 182 7 +339.63 ± 44.35
482947 ncm-dbt-03 577602 500 233 36 231 +144.71 ± 12.26 0 2 55 187 6 +349.43 ± 46.59
482946 ncm-dbt-05 598788 500 230 38 232 +140.62 ± 12.44 0 1 63 179 7 +330.23 ± 43.2
482945 ncm-dbt-02 592202 500 226 36 238 +138.99 ± 12.09 0 3 57 187 3 +336.46 ± 45.77
482944 ncm-dbt-01 583279 500 227 41 232 +135.76 ± 12.42 0 4 59 184 3 +324.17 ± 44.97
482943 ncm-dbt-04 569071 500 224 31 245 +141.44 ± 11.98 0 2 57 187 4 +342.85 ± 45.71
482942 ncm-dbt-03 576292 500 232 38 230 +142.25 ± 11.73 0 0 61 184 5 +342.85 ± 43.79
482941 ncm-dbt-05 601001 500 228 39 233 +138.18 ± 12.73 0 2 64 177 7 +321.19 ± 42.95
482940 ncm-dbt-02 589240 500 219 43 238 +127.76 ± 12.65 0 5 66 177 2 +298.62 ± 42.41
482939 ncm-dbt-01 583154 500 230 40 230 +138.99 ± 12.3 0 2 61 182 5 +330.23 ± 44.08
482938 ncm-dbt-03 576578 500 225 43 232 +132.54 ± 12.12 0 0 73 172 5 +306.84 ± 39.69
482937 ncm-dbt-04 569310 500 236 45 219 +139.81 ± 12.87 0 3 60 180 7 +327.18 ± 44.54
482936 ncm-dbt-05 601981 500 220 34 246 +135.76 ± 12.21 0 3 61 183 3 +324.17 ± 44.15
482935 ncm-dbt-02 590438 500 228 44 228 +134.15 ± 12.47 0 2 67 176 5 +312.48 ± 41.9
482934 ncm-dbt-01 582736 500 230 39 231 +139.81 ± 13.07 0 3 61 178 8 +324.17 ± 44.15
482933 ncm-dbt-05 607196 500 229 35 236 +142.25 ± 12.58 0 3 56 185 6 +339.63 ± 46.2
482932 ncm-dbt-04 568355 500 222 41 237 +131.74 ± 11.52 0 1 68 180 1 +315.35 ± 41.44
482931 ncm-dbt-03 577192 500 221 34 245 +136.56 ± 11.76 0 1 64 182 3 +327.18 ± 42.83
482930 ncm-dbt-02 591469 500 230 28 242 +148.85 ± 11.83 0 4 43 200 3 +377.87 ± 52.99
482929 ncm-dbt-01 584285 500 221 47 232 +126.17 ± 12.68 0 3 74 169 4 +288.06 ± 39.79
482928 ncm-dbt-05 623017 500 236 28 236 +153.86 ± 12.22 0 1 49 191 9 +377.87 ± 49.47
482927 ncm-dbt-04 567442 500 218 31 251 +136.56 ± 12.59 0 4 59 183 4 +324.17 ± 44.97
482926 ncm-dbt-03 573365 500 228 38 234 +138.99 ± 12.09 0 2 60 184 4 +333.32 ± 44.47

Commit

Commit ID 49f8e667c0ebf146f3ce5a1ea2d49ac78b9f777e
Author Joost VandeVondele
Date 2026-08-19 16:38:46 UTC
Avoid UB decoding LEB128, and guard against corrupted files read_leb_128_detail accumulated decoded bytes into a signed IntType. For int32 values, a 5-byte LEB128 encoding reaches shift 28, which causes signed-integer-overflow UB. Accumulate into u32 instead and cast to IntType only after sign extension. Also harden the network reader against short or corrupted files: read_leb_128_detail now tracks the number of bytes actually read and fails the stream on a short read; read_header bounds the description string by the stream rather than a declared size; and the LEB128 magic and byte-balance checks are promoted from asserts to stream failures. closes https://github.com/official-stockfish/Stockfish/pull/7066 No functional change Co-authored-by: ppigazzini <pasquale.pigazzini@gmail.com>
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