CVE Vulnerabilities


Out-of-bounds Read

Published: Nov 12, 2017 | Modified: Oct 03, 2019
CVSS 3.x
CVSS 2.x

The png_load function in lib/png.c in SWFTools 0.9.2 does not properly validate a multiplication of width and bits-per-pixel values, which allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file, as demonstrated by an erroneous png_load call that occurs because of incorrect integer data types in png2swf.


The software reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name Vendor Start Version End Version
Swftools Swftools 0.9.2 0.9.2
Swftools Ubuntu artful *
Swftools Ubuntu bionic *
Swftools Ubuntu cosmic *
Swftools Ubuntu disco *
Swftools Ubuntu trusty *
Swftools Ubuntu upstream *
Swftools Ubuntu xenial *
Swftools Ubuntu zesty *

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.