Use-after-free vulnerability in the imgContainer::InternalAddFrameHelper function in src/imgContainer.cpp in libpr0n in Mozilla Firefox 3.6 before 3.6.2 allows remote attackers to cause a denial of service (heap memory corruption and application crash) or possibly execute arbitrary code via a multipart/x-mixed-replace animation in which the frames have different bits-per-pixel (bpp) values.
Vulnerabilidad uso después de la liberación (use-after-free) en la función imgContainer::InternalAddFrameHelper en src/imgContainer.cpp en libpr0n en Mozilla Firefox v3.6 anterior a v3.6.2 permite a atacantes remotos producir una denegación de servicio (corrupción de la memoria de la pila y caída de la aplicación) o posiblemente ejecución arbitraria de código a través de una animación multipart/x-mixed-replace en el que los frames tienen valores diferentes de bit por pixel (bpp).
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Mozilla Firefox. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the libpr0n library which is responsible for handling image caching and animation and is due to the way the application handles animations received from the server via the multipart/x-mixed-replace mimetype. During a case where the bits-per-pixel changes, the application will free a pointer and then can be made to reuse the freed pointer later. This can lead to code execution under the context of the application.
