Crash caused by Buffer Overread in TBitArray operator < function

UE - Foundation - Core - Aug 29, 2018

A licensee has reported a crash that is caused by a Buffer Overread in TBitArray's operator < function. While the licensee did not provide reproduction steps, the crash is apparent from looking at t ...

Crash on loading pre-4.20 cloth data when compute skin cache is enabled in 4.21

UE - Graphics Features - Mar 19, 2019

According to information from the licensee, the else clause was added to "FSkeletalMeshLODModel::(GetClothMappingData()" at CL 4437969 , but if it is the cloth data existing from 4.20 or earlier, it ...

Compile on load crashes for classes within an abstract class

UE - Gameplay - Blueprint Compiler - Feb 20, 2021

When compiling on load in -game, a blueprint class that inherits from a native class that is marked within and the class that it is within is abstract, a crash will occur when FBlueprintCompilationM ...

Incorrect volume bounds check in FTranslucentLightInjectionCollector::AddLightForInjection

UE - Graphics Features - Apr 8, 2025

The 'VolumeBounds' array in FTranslucentLightInjectionCollector::AddLightForInjection is accessed as a pointer instead of with 'VolumeCascadeIndex' and thus fails bounds checks for the outer volume. ...

Blueprints with Input action events are dirtied and upon being opened

UE - Gameplay - Blueprint Editor - Aug 10, 2017

Opening a blueprint that has an input event in it cause the blueprint to become dirtied and require compiling. Regression?: Yes This did not occur in 4.16.3-3561208+++UE4+Release-4.16 Versions tes ...

Level Sequence option "Allow Level Edits Only" causes Frame Rate drop when used

UE - Anim - Sequencer - Aug 15, 2017

When using the new option "Allow Level Edits Only" there is a drastic frame rate drop while playing the sequencer. This frame rate drops when only using this option. Versions Tested: 4.16.3 - CL: 3 ...

Property Table rendering very slow in 4.19 (regression)

Tools - Feb 8, 2018

Editor frame rate is very slow rendering the Property Table in 4.19.  This is a regression from 4.18 Showing frame-rate in the editor with the property editor open shows really high GPU time: [Ima ...

RecastNavMesh is not generated at loaded sublevel

UE - AI - Aug 16, 2018

RecastNavMesh is not generated at the sub level dynamically added in C ++ in 4.20. In 4.18, 4.19 it was generated normally. Probably, changes to the large number about NavMesh systems from 4.19 to ...

Certain combined Linear/Angular movements cause Client to freeze for several seconds

UE - Simulation - Physics - May 24, 2019

When using Replicated Movement, certain combined linear/angular movements cause the client to freeze for several seconds and then catch up to the server. This is a regression from 4.21.2 (CL-4753647 ...

RemoveAxisMapping() removes axis mappings of the same key regardless of Scale value

UE - Gameplay - Jun 26, 2019

When you remove an axis mapping using a specific key it will remove all mappings even if they have separate scales. The user found a fix that I verified that worked. In "InputSettings.cpp", which i ...