CVE-2020-24996

There is an invalid memory access in the function TextString::~TextString() located in Catalog.cc in Xpdf 4.0.2. It can be triggered by (for example) sending a crafted pdf file to the pdftohtml binary, which allows a remote attacker to cause a Denial of Service (Segmentation fault) or possibly have unspecified other impact.

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://forum.xpdfreader.com/viewtopic.php?f=3\u0026t=42028