firefox: memory safety bugs showing evidence of memory corruption leading to run arbitrary code

Mozilla developers and community members reported memory safety bugs present in Firefox 63. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 64.

nss: Cache side-channel variant of the Bleichenbacher attack

A cached side channel attack during handshakes using RSA encryption could allow for the decryption of encrypted content. This is a variant of the Adaptive Chosen Ciphertext attack (AKA Bleichenbacher attack) and affects all NSS versions prior to NSS 3.41.

firefox: mixed content warning is not displayed when HTTPS page loads a favicon over HTTP

If a site is loaded over a HTTPS connection but loads a favicon resource over HTTP, the mixed content warning is not displayed to users. This vulnerability affects Firefox < 63.

firefox: WebBrowserPersist uses incorrect origin information

The internal WebBrowserPersist code does not use correct origin context for a resource being saved. This manifests when sub-resources are loaded as part of "Save Page As..." functionality. For example, a malicious page could recover a visitor's Windows username and NTLM hash by including resources otherwise unreachable to the malicious page, if they can convince the visitor to save the complete web page. Similarly, SameSite cookies are sent on cross-origin requests when the "Save Page As..." menu item is selected to save a page, which can result in saving the wrong version of resources based on those cookies. This vulnerability affects Firefox < 63.

firefox: special resource URI parsing leading to denial of service

Some special resource URIs will cause a non-exploitable crash if loaded with optional parameters following a '?' in the parsed string. This could lead to denial of service (DOS) attacks. This vulnerability affects Firefox < 63.

In private browsing mode on Firefox for Android, favicons are cached in the cache/icons folder as they are in non-private mode. This allows information leakage of sites visited during private browsing sessions. *Note: this issue only affects Firefox for Android. Desktop versions of Firefox are unaffected.*. This vulnerability affects Firefox < 63.

firefox: Spoofing of protocol registration notification bar

When a new protocol handler is registered, the API accepts a title argument which can be used to mislead users about which domain is registering the new protocol. This may result in the user approving a protocol handler that they otherwise would not have. This vulnerability affects Firefox < 63.

firefox: Content Security Policy bypass through stylesheet injection in resource URIs

By using the reflected URL in some special resource URIs, such as chrome:, it is possible to inject stylesheets and bypass Content Security Policy (CSP). This vulnerability affects Firefox < 63.

Mozilla: WebExtension content scripts can execute in disallowed contexts

A vulnerability where a WebExtension can run content scripts in disallowed contexts following navigation or other events. This allows for potential privilege escalation by the WebExtension on sites where content scripts should not be run. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.

Mozilla: WebExtension bypass of domain restrictions through header rewriting

By rewriting the Host: request headers using the webRequest API, a WebExtension can bypass domain restrictions through domain fronting. This would allow access to domains that share a host that are otherwise restricted. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.

Mozilla: Integer overflow during Unicode conversion while loading JavaScript

A potential vulnerability was found in 32-bit builds where an integer overflow during the conversion of scripts to an internal UTF-16 representation could result in allocating a buffer too small for the conversion. This leads to a possible out-of-bounds write. *Note: 64-bit builds are not vulnerable to this issue.*. This vulnerability affects Firefox < 63, Firefox ESR < 60.3, and Thunderbird < 60.3.

Mozilla: HTTP Live Stream audio data is accessible cross-origin

During HTTP Live Stream playback on Firefox for Android, audio data can be accessed across origins in violation of security policies. Because the problem is in the underlying Android service, this issue is addressed by treating all HLS streams as cross-origin and opaque to access. *Note: this issue only affects Firefox for Android. Desktop versions of Firefox are unaffected.*. This vulnerability affects Firefox < 63, Firefox ESR < 60.3, and Thunderbird < 60.3.

firefox: memory safety bugs showing evidence of memory corruption leading to run arbitrary code

Mozilla developers and community members reported memory safety bugs present in Firefox 62. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 63.

Mozilla: Crash in TransportSecurityInfo due to cached data

A potentially exploitable crash in TransportSecurityInfo used for SSL can be triggered by data stored in the local cache in the user profile directory. This issue is only exploitable in combination with another vulnerability allowing an attacker to write data into the local cache or from locally installed malware. This issue also triggers a non-exploitable startup crash for users switching between the Nightly and Release versions of Firefox if the same profile is used. This vulnerability affects Thunderbird < 60.2.1, Firefox ESR < 60.2.1, and Firefox < 62.0.2.

nss: ServerHello.random is all zeros when handling a v2-compatible ClientHello

When handling a SSLv2-compatible ClientHello request, the server doesn't generate a new random value but sends an all-zero value instead. This results in full malleability of the ClientHello for SSLv2 used for TLS 1.2 in all versions prior to NSS 3.39. This does not impact TLS 1.3.

Mozilla: Setting a master password post-Firefox 58 does not delete unencrypted previously stored passwords

If a user saved passwords before Firefox 58 and then later set a master password, an unencrypted copy of these passwords is still accessible. This is because the older stored password file was not deleted when the data was copied to a new format starting in Firefox 58. The new master password is added only on the new file. This could allow the exposure of stored password data outside of user expectations. This vulnerability affects Firefox < 62, Firefox ESR < 60.2.1, and Thunderbird < 60.2.1.

Mozilla: Addressbar spoofing with javascript URI on Firefox for Android

The displayed addressbar URL can be spoofed on Firefox for Android using a javascript: URI in concert with JavaScript to insert text before the loaded domain name, scrolling the loaded domain out of view to the right. This can lead to user confusion. *This vulnerability only affects Firefox for Android < 62.*

Mozilla: Memory safety bugs fixed in Firefox 62

Memory safety bugs present in Firefox 61. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 62.

thunderbird: Using form to exfiltrate encrypted mail part by pressing enter in form field

Plaintext of decrypted emails can leak through by user submitting an embedded form by pressing enter key within a text input field. This vulnerability affects Thunderbird < 52.9.

thunderbird: S/MIME plaintext can be leaked through HTML reply/forward

dDecrypted S/MIME parts hidden with CSS or the plaintext HTML tag can leak plaintext when included in a HTML reply/forward. This vulnerability affects Thunderbird < 52.9.