CVE-2021-3520: lz4_project lz4 Integer Overflow or Wraparound

Vulnerability summary

CVE-2021-3520 is a critical (CVSS 9.8) Integer Overflow or Wraparound vulnerability in lz4_project lz4. EPSS estimates a 3.40% chance of exploitation in the next 30 days, higher than 88.6% of scored vulnerabilities.

Timeline

1. 02-06-2021
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

There's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading to calling of memmove() on a negative size argument, causing an out-of-bounds write and/or a crash. The greatest impact of this flaw is to availability, with some potential impact to confidentiality and integrity as well.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.