Bug 1333332 (CVE-2016-4488) - CVE-2016-4488 gcc: Invalid write due to a use-after-free to array ktypevec
Summary: CVE-2016-4488 gcc: Invalid write due to a use-after-free to array ktypevec
Alias: CVE-2016-4488
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1333388 1333389
Blocks: 1333338
TreeView+ depends on / blocked
Reported: 2016-05-05 10:10 UTC by Andrej Nemec
Modified: 2021-02-17 03:55 UTC (History)
13 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2017-08-08 11:22:31 UTC

Attachments (Terms of Use)

Description Andrej Nemec 2016-05-05 10:10:23 UTC
A vulnerability was found in gcc. There is a variable ksize storing the amount of allocated memory for the array ktypevec. ksize being zero (0) indicates that some memory must be allocated upon the first write. When more memory is needed, both ksize and the memory are doubled during reallocation. At some point the memory for the array is freed (in squangle_mop_up) but the value of ksize remains. Since ksize is not 0, there is no indication that new memory must be allocated when there is another write to the array. This allows a malicious attacker to write arbitrary content to freed memory.

External references:


Upstream fix:


Comment 1 Andrej Nemec 2016-05-05 12:11:01 UTC
Created msp430-gcc tracking bugs for this issue:

Affects: fedora-all [bug 1333388]

Comment 2 Andrej Nemec 2016-05-05 12:11:07 UTC
Created mingw-gcc tracking bugs for this issue:

Affects: epel-all [bug 1333389]

Comment 3 Raphael Sanchez Prudencio 2017-08-08 10:57:30 UTC

Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

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