Bug 1820331 (CVE-2020-6096) - CVE-2020-6096 glibc: signed comparison vulnerability in the ARMv7 memcpy function
Summary: CVE-2020-6096 glibc: signed comparison vulnerability in the ARMv7 memcpy func...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2020-6096
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1820332
Blocks: 1820333
TreeView+ depends on / blocked
 
Reported: 2020-04-02 18:37 UTC by Guilherme de Almeida Suckevicz
Modified: 2020-04-22 14:23 UTC (History)
15 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
A signed comparison vulnerability was found in GNU libc in the ARMv7 implementation of memcpy(). The flaw affects the third argument to memcpy() that specifies the number of bytes to copy. An underflow on the third argument could lead to undefined behavior such as out-of-bounds memory write and potentially remote code execution.
Clone Of:
Environment:
Last Closed: 2020-04-16 16:32:18 UTC


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Description Guilherme de Almeida Suckevicz 2020-04-02 18:37:20 UTC
An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000. Calling memcpy() (on ARMv7 targets that utilize the GNU glibc implementation) with a negative value for the 'num' parameter results in a signed comparison vulnerability. If an attacker underflows the 'num' parameter to memcpy(), this vulnerability could lead to undefined behavior such as writing to out-of-bounds memory and potentially remote code execution. Furthermore, this memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data.

Reference:
https://sourceware.org/bugzilla/show_bug.cgi?id=25620

Comment 1 Guilherme de Almeida Suckevicz 2020-04-02 18:38:15 UTC
Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1820332]

Comment 5 Product Security DevOps Team 2020-04-16 16:32:18 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-6096

Comment 6 Mauro Matteo Cascella 2020-04-16 16:42:13 UTC
Statement:

Red Hat Enterprise Linux only supports the 64-bit ARM architecture (AArch64) which does not include the vulnerable implementation of `memcpy()`. Therefore, all versions of glibc as shipped with RHEL are not affected by this flaw.

Comment 8 Mauro Matteo Cascella 2020-04-17 13:05:56 UTC
External References:

https://sourceware.org/bugzilla/attachment.cgi?id=12334


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