Use-after-free vulnerability in the nsIPresShell::GetPresContext function in the PresShell (aka presentation shell) implementation in Mozilla Firefox before 25.0, Firefox ESR 17.x before 17.0.10 and 24.x before 24.1, Thunderbird before 24.1, Thunderbird ESR 17.x before 17.0.10, and SeaMonkey before 2.22 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption and application crash) via vectors involving a CANVAS element, a mozTextStyle attribute, and an onresize event.

Use-after-free vulnerability in the nsDocLoader::doStopDocumentLoad function in Mozilla Firefox before 25.0, Firefox ESR 17.x before 17.0.10 and 24.x before 24.1, Thunderbird before 24.1, Thunderbird ESR 17.x before 17.0.10, and SeaMonkey before 2.22 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via vectors involving a state-change event during an update of the offline cache.

The cycle collection (CC) implementation in Mozilla Firefox before 25.0, Firefox ESR 24.x before 24.1, Thunderbird before 24.1, and SeaMonkey before 2.22 does not properly determine the thread for release of an image object, which allows remote attackers to execute arbitrary code or cause a denial of service (race condition and application crash) via a large HTML document containing IMG elements, as demonstrated by the Never-Ending Reddit on reddit.com.

The JavaScript engine in Mozilla Firefox before 25.0, Firefox ESR 17.x before 17.0.10 and 24.x before 24.1, Thunderbird before 24.1, Thunderbird ESR 17.x before 17.0.10, and SeaMonkey before 2.22 does not properly allocate memory for unspecified functions, which allows remote attackers to conduct buffer overflow attacks via a crafted web page.

The SELECT element implementation in Mozilla Firefox before 25.0, Firefox ESR 24.x before 24.1, Thunderbird before 24.1, and SeaMonkey before 2.22 does not properly restrict the nature or placement of HTML within a dropdown menu, which allows remote attackers to spoof the address bar or conduct clickjacking attacks via vectors that trigger navigation off of a page containing this element.

Unspecified vulnerability in the browser engine in Mozilla Firefox before 25.0, Firefox ESR 24.x before 24.1, Thunderbird before 24.1, and SeaMonkey before 2.22 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 25.0, Firefox ESR 17.x before 17.0.10 and 24.x before 24.1, Thunderbird before 24.1, Thunderbird ESR 17.x before 17.0.10, and SeaMonkey before 2.22 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

The RC4 algorithm, as used in the TLS protocol and SSL protocol, has many single-byte biases, which makes it easier for remote attackers to conduct plaintext-recovery attacks via statistical analysis of ciphertext in a large number of sessions that use the same plaintext.