# Use after free bug in FreeRTOS+FAT 160919a

**URL:** <https://forums.freertos.org/t/use-after-free-bug-in-freertos-fat-160919a/7945>\
**Category:** Kernel\
**Created:** [July 1, 2019, 1:44pm UTC](https://forums.freertos.org/t/use-after-free-bug-in-freertos-fat-160919a/7945 "2019-07-01T13:44:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [July 1, 2019, 1:44pm UTC](https://forums.freertos.org/t/use-after-free-bug-in-freertos-fat-160919a/7945/1 "2019-07-01T13:44:24Z")

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**[jjr-simiatec](https://sourceforge.net/u/jjr-simiatec/)** wrote on [Monday, July 01, 2019](https://sourceforge.net/p/freertos/discussion/382005/thread/6e3856e518/#63a8):

Version: FreeRTOS-Plus-FAT-160919a-MIT

In ff\_file.c: FF\_Close() @ line 2970:

```
ffconfigFREE( pxFile );

if( FF_isERR( xError ) == pdFALSE )
{
    xError = FF_FlushCache( pxFile->pxIOManager ); /* Ensure all modified blocks are flushed to disk! */
}

```

Fix: move ffconfigFREE(…) after the if block.

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<div class="post-metadata">

**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [November 16, 2019, 3:10pm UTC](https://forums.freertos.org/t/use-after-free-bug-in-freertos-fat-160919a/7945/2 "2019-11-16T15:10:06Z")

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**[jjr-simiatec](https://sourceforge.net/u/jjr-simiatec/)** wrote on [Saturday, November 16, 2019](https://sourceforge.net/p/freertos/discussion/382005/thread/6e3856e518/#d277):

_deleted_

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<div class="post-metadata">

**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [November 16, 2019, 3:10pm UTC](https://forums.freertos.org/t/use-after-free-bug-in-freertos-fat-160919a/7945/3 "2019-11-16T15:10:17Z")

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**[jjr-simiatec](https://sourceforge.net/u/jjr-simiatec/)** wrote on [Saturday, November 16, 2019](https://sourceforge.net/p/freertos/discussion/382005/thread/6e3856e518/#5b16):

Assigned CVE-2019-18178 and subsequently fixed.

References:

[https://sourceforge.net/p/freertos/bugs/195/](https://sourceforge.net/p/freertos/bugs/195/)  
[https://sourceforge.net/p/freertos/bugs/199/](https://sourceforge.net/p/freertos/bugs/199/)