[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
pylint (changelog)	4.0.6 → 4.0.9

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Pylint: Arbitrary code execution via pickle deserialization of the stats cache in PYLINT_HOME

CVE-2026-114608 / GHSA-22qq-2fwx-7p67

More information

Details

Impact

Since 2006 / pylint 0.15.2, pylint caches its stats as pickles in PYLINT_HOME and reload them on the next run with pickle.load. Someone without access to the configuration or linted code, but with access to the cache directory (predictable PYLINT_HOME on a multi-user host) can write a crafted pickle that will runs arbitrary code when pylint access its stat cache.

Patches

From pylint 4.0.9, the result cache is now stored as JSON instead of pickle, preventing code-execution.

Workarounds

Until upgrading do not point PYLINT_HOME to an untrusted, shared, or group-writable directory. The default value, ~/.cache/pylint, is writable only by the user running pylint.

Credits

• Reported privately via Tidelift coordinated disclosure (Dan Lenz).

Severity

• CVSS Score: 5.4 / 10 (Medium)
• Vector String: CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/pylint-dev/pylint/security/advisories/GHSA-22qq-2fwx-7p67
• https://nvd.nist.gov/vuln/detail/CVE-2026-114608
• https://github.com/pylint-dev/pylint/commit/58c87cffca9de2b3e89aa07b89686cbc90cfea2d
• https://github.com/pylint-dev/pylint/commit/5b241f66318220e9ba7b21ca631fbfe8e77682ca
• https://github.com/pylint-dev/pylint/releases/tag/v4.0.9
• https://github.com/advisories/GHSA-22qq-2fwx-7p67

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

pylint-dev/pylint (pylint)

v4.0.9

Compare Source

What's new in Pylint 4.0.9?

Release date: 2026-09-23

Security Fixes

• Someone without access to the configuration or linted code, but with access
  to the cache directory (predictable PYLINT_HOME on a multi-user host) can no
  longer write a crafted pickle that will runs arbitrary code when pylint access its
  stat cache. The result cache is now stored as JSON instead of pickle,
  preventing code-execution. The workaround is upgrading or not pointing PYLINT_HOME
  to an untrusted, shared, or group-writable directory. The default value, ~/.cache/pylint,
  is writable only by the user running pylint. (CVE with the same information pending)

False Positives Fixed

• Fixed a false positive for no-self-use on a method that only uses
  self before a locally defined class (or other nested method), because
  the checker's could-be-a-function tracking state was not restored after
  visiting the nested method.

  Closes #​3705

• Fix a false positive for :ref:not-callable when calling functions constructed with
  types.FunctionType or types.LambdaType.

  Closes #​7500

• Fix a false positive for unnecessary-direct-lambda-call when a directly called
  lambda in a class body wraps a comprehension containing an assignment expression.
  PEP 572 makes that a SyntaxError without the lambda's scope, so following the
  message produced code that would not compile.

  Closes #​9294

• Fix a false positive for :ref:unnecessary-ellipsis when an ellipsis is the
  sole body statement of a method defined on a Protocol.

  Closes #​9319

• Fix a false positive for :ref:bad-exception-cause when the bases of the class
  being raised from cannot be inferred, such as an exception deriving from a
  C extension class. :ref:raising-non-exception and
  :ref:catching-non-exception already guard the same inherit_from_std_ex
  helper with has_known_bases.

  Refs #​11399

False Negatives Fixed

• method-hidden is no longer silenced when the hidden method shares its name with
  a builtin function or with a function defined at module level. Only members of the
  ancestor classes themselves can excuse the method now.

  Refs #​11361

Other Bug Fixes

• Fix a block-scoped # pylint: disable= directive placed inside an if
  body leaking into sibling elif/else blocks for messages such as
  stop-iteration-return, which default to a line-based (rather than
  node-based) message scope.

  Closes #​3136

• Fix a false positive for declare-non-slot when a class variable is
  annotated with ClassVar without an initial value.

  Closes #​9950

• Fix a crash in the no-member checker when attribute lookup raises an
  InferenceError.

  Closes #​11356

• Fix a crash in the unnecessary-default-type-args check when a Generator
  or AsyncGenerator subscript holds an empty tuple, such as Generator[()].

  Closes #​11357

• Fix a crash in method-hidden when a method shadows a name that builtins
  binds to a node without a statement, such as help or license. Every class
  inherits from object, which lives in the builtins module, so no base class
  was needed to trigger it.

  Closes #​11361
  Closes #​8079

v4.0.8

Compare Source

What's new in Pylint 4.0.8?

Release date: 2026-08-29

False Positives Fixed

• Fix a false positive for :ref:unspecified-encoding when an open call uses a mode
  argument that cannot be inferred.

  Closes #​10201

• Fix a false positive for invalid-name (C0103) on names assigned in an
  if __name__ == "__main__": block. Such a block reads like a script body, so
  a name there is now accepted if it matches either the constant or the variable
  naming style.

  Closes #​10766

• Fix false positives for :ref:invalid-str-returned, :ref:invalid-repr-returned,
  :ref:invalid-format-returned, :ref:invalid-bytes-returned, :ref:invalid-hash-returned,
  :ref:invalid-index-returned, :ref:invalid-length-returned,
  :ref:invalid-length-hint-returned, :ref:invalid-getnewargs-returned and
  :ref:invalid-getnewargs-ex-returned when the returned value is an instance of a
  subclass of the expected builtin type, such as self in a str subclass or a
  namedtuple.

  Closes #​11306

• Fix false positives for :ref:bad-string-format-type when the argument is an
  instance of a subclass of int, float or str, such as bool or an
  IntEnum member formatted with %d.

  Closes #​11315

False Negatives Fixed

• redundant-unittest-assert now also flags assertEqual and assertNotEqual
  when both compared values are constants, e.g. self.assertEqual(5, 5).

  Closes #​11321

Other Bug Fixes

• Fix a crash in the docparams extension when a raised name does not infer to an exception, such as raise sum or raise some_module. Such objects have no ancestors(), which aborted the whole file with an astroid-error fatal message.

  Closes #​11228

• Fix a crash in the use-yield-from checker (AttributeError: 'Subscript' object has no attribute 'name') when a loop target is a subscript, attribute, or tuple.

  Closes #​11286

• Fix a crash in the docparams extension (AttributeError: 'AssignName' object has no attribute 'decorators') when a class has non-function attributes sharing the name of a property setter.

  Closes #​11287

Other Changes

• Upgrade the isort upper bound so isort 9 can be installed alongside pylint.

  Closes #​11351

v4.0.7

Compare Source

What's new in Pylint 4.0.7?

Release date: 2026-08-09

False Positives Fixed

• Fix a false positive for invalid-name when a module-level variable is assigned
  an instance of a TypedDict subclass. Such a name is a value, not a type
  definition, so it is now checked against the constant or variable regex instead
  of class-rgx.

  Closes #​11231

Other Bug Fixes

• Fix a crash in the bad-open-mode check when the mode argument of
  open is the NotImplemented constant (Python >= 3.14).

  Closes #​11099

• Fix a crash in the not-context-manager and not-async-context-manager
  checks when the context manager infers to a value without a name, such as the
  slice returned by with slice(...) / async with slice(...).

  Closes #​11102

• Fix a false positive for nested-min-max (W3301) when the inner min/max call carries a keyword argument such as key=. Flattening the call dropped the keyword and changed the result, so nested calls whose inner call has keyword arguments are no longer flagged.

  Closes #​11130

• Fix a false suggestion from nested-min-max (W3301): when rewriting a nested min/max into a splat call, arguments positioned after the splatted call were silently dropped, so the suggested code changed the result.

  Closes #​11134

• Fix a false positive for too-many-locals (R0914): PEP 695 type parameters, i.e. the T1 and T2 in a generic def f[T1, T2] signature, were counted as local variables. They are type-system constructs, not runtime locals, and are now excluded from the local-variable count.

  Closes #​11136

• Fix literal-comparison (R0123) emitting a corrupted suggestion for identifiers
  that contain is (e.g. axis is 5 was rendered ax== == 5). The suggestion
  is now rebuilt from the operands and operator.

  Closes #​11146

• Fix false positives in bad-string-format-type (E1307) for valid % formatting:
  %i/%u applied to a float (both truncate like %d) and %a applied to any
  non-int type (%a is type-agnostic like %s/%r).

  Closes #​11147

• Fix a false positive for :ref:useless-parent-delegation when an override changes
  the default value of a positional-only parameter.

  Closes #​11148

• Fixed a crash in comparison-with-callable when comparing a lambda assigned as a class attribute.

  Closes #​11175

• too-many-lines could be reported at the line of a # pylint: disable=too-many-lines
  pragma found in a previously linted module. Pragma positions are now reset between
  modules, so the message is reported at line 1 (or at the current module's own pragma)
  regardless of which files were linted before.

  Refs #​11191

• Fix a crash when a call unpacks a dictionary whose keys are not string
  constants, e.g. copy.copy(**{-1: 1}).

  Closes #​11222

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