Issues

• Upgrade bundled Expat to 2.9.0 (e.g. for fixes to two vulnerabilities)

  3.113.123.133.143.153.16extension-modulestopic-XMLtype-security
  python/cpython#158876 · Filter by author hartwork opened on Oct 5, 2026
  

• _pickle crashes when read() returns a bytes subclass for large payloads

  3.15extension-modulestype-crash
  python/cpython#158841 · Filter by author error-3317 opened on Oct 5, 2026
  2

• del list[index] never reallocates the array

  3.143.153.16interpreter-coreperformancetype-bugtype-refactor
  python/cpython#158592 · Filter by author x42005e1f opened on Oct 2, 2026
  6

• 3.14: objects de-immortalized by old stable-ABI extensions break truthiness checks in specialized bytecode

  3.143.153.16interpreter-coretype-bug
  python/cpython#158401 · Filter by author clairernovotny opened on Sep 29, 2026
  4

• asyncio.subprocess blocked event loop unexpectedly on MacOS

  3.143.153.16stdlibtopic-asynciotype-bug
  python/cpython#158287 · Filter by author starstreammm opened on Sep 27, 2026
  8

• gh-133879: Announce final release in What's New in Python 3.15

  3.15docsneeds backport to 3.15release-blockerskip news
  Unread
  python/cpython#158256·hugovk opened Sep 26, 2026 · Updated Oct 3, 2026·Draft
  1

  

• pickle.dumps() creates and discards an AttributeError on every call since 3.13.1

  3.133.143.153.16extension-modulestype-bug
  python/cpython#158126 · Filter by author ashm-dev opened on Sep 24, 2026
  2

• IDLE on macOS 27 hangs when a menu command opens a dialog

  3.133.143.153.16OS-mactopic-tkintertype-bug
  python/cpython#158053 · Filter by author Universe-Of-The-Creator opened on Sep 24, 2026
  23

• os.environ.clear() now leaves the C environ pointer NULL, which crashes Tcl/Tk (tkinter) on the next Tcl_CreateInterp

  3.15extension-modulestype-crash
  python/cpython#157741 · Filter by author YuanchengJiang opened on Sep 18, 2026
  3

• lazy import a.b as c incorrectly binds to a.b.b

  3.153.16interpreter-coretopic-lazy-importstype-bug
  python/cpython#157614 · Filter by author grgalex opened on Sep 16, 2026
  7

• CPython 3.13-3.15 concurrency and memory-safety issue reports

  3.133.143.15extension-modulesinterpreter-corependingtopic-free-threadingtype-bug
  python/cpython#157601 · Filter by author BaihongChen opened on Sep 16, 2026
  2

• Proxy-Authorization headers are preserved on redirects

  3.10 (EOL)3.113.123.133.143.153.16stdlibtype-security
  python/cpython#157583 · Filter by author sethmlarson opened on Sep 15, 2026

• Structseq objects created with PyStructSequence_New() are not tracked by the GC

  3.133.143.153.16interpreter-coretype-bug
  python/cpython#157443 · Filter by author serhiy-storchaka opened on Sep 13, 2026

• Memory leak on interpreter shutdown when reference cycle exists between structseq type and its instance

  3.143.153.16type-bug
  python/cpython#157176 · Filter by author ashm-dev opened on Sep 8, 2026
  3

• ast.AST.__repr__ can crash on missing _fields

  3.143.153.16interpreter-coretype-crash
  python/cpython#156909 · Filter by author johnslavik opened on Sep 3, 2026
  

• deque.index result changed in 3.14.7 when a bound's __index__ mutates the deque

  3.143.153.16docs
  python/cpython#156743 · Filter by author samuelcolvin opened on Aug 31, 2026
  4

• Conditional annotations are always included in STRING annotations

  3.143.153.16stdlibtype-bug
  python/cpython#156515 · Filter by author DavidCEllis opened on Aug 28, 2026

• GC may hold frames longer than necessary

  3.153.16interpreter-coretype-bug
  python/cpython#156425 · Filter by author sergey-miryanov opened on Aug 26, 2026
  

• LOAD_ATTR specialization for ModuleType subclasses bypasses data descriptors on the subclass (3.14 regression)

  3.143.153.16interpreter-coretype-bug
  python/cpython#156399 · Filter by author GrahamDumpleton opened on Aug 26, 2026

• PyRefTracer_DESTROY is not called for objects deferred by the trashcan mechanism

  3.143.153.16type-bug
  python/cpython#156371 · Filter by author corona10 opened on Aug 25, 2026
  2

  

• zlib.crc32_combine() hangs on a negative length and adler32_combine() returns rubbish

  3.153.16extension-modulestype-bug
  python/cpython#156180 · Filter by author StanFromIreland opened on Aug 21, 2026
  

• Keyword typo suggestions differ between file and string tokenizers

  3.143.153.16interpreter-coretopic-parsertype-bug
  python/cpython#156047 · Filter by author m-aciek opened on Aug 19, 2026
  4

• Memory exhaustion via crafted zip file

  3.10 (EOL)3.113.123.133.143.153.16stdlibtype-security
  python/cpython#156002 · Filter by author encukou opened on Aug 18, 2026
  3

• LOAD_ATTR does not specialize after replacing an instance's __dict__

  3.143.153.16interpreter-coreperformancetype-bug
  python/cpython#155962 · Filter by author koxudaxi opened on Aug 17, 2026

• marshal.dumps() takes exponential time on nested frozensets

  3.143.153.16interpreter-coretype-bug
  python/cpython#155901 · Filter by author serhiy-storchaka opened on Aug 16, 2026
  1