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Ubuntu Security Notice USN-4968-2
May 31, 2021

lz4 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

LZ4 could be made to crash or run programs if it opened a specially crafted
file.

Software Description:
- lz4: Extremely fast compression algorithm

Details:

USN-4968-1 fixed a vulnerability in LZ4. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory details:

 It was discovered that LZ4 incorrectly handled certain memory operations.
 If a user or automated system were tricked into uncompressing a specially-
 crafted LZ4 file, a remote attacker could use this issue to cause LZ4 to
 crash, resulting in a denial of service, or possibly execute arbitrary
 code.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 ESM:
  liblz4-1                        0.0~r131-2ubuntu2+esm1

Ubuntu 14.04 ESM:
  liblz4-1                        0.0~r114-2ubuntu1+esm2

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-4968-2
  https://ubuntu.com/security/notices/USN-4968-1
  CVE-2021-3520