CVE-2020-12422: Security Vulnerabilities fixed in Firefox 78

Mozilla Foundation Security Advisory 2020-24

Announced

June 30, 2020

Impact

high

Products

Firefox

Fixed in

• Firefox 78

#CVE-2020-12415: AppCache manifest poisoning due to url encoded character processing

Reporter

Kevin Higgs

Impact

high

Description

When %2F was present in a manifest URL, Firefox’s AppCache behavior may have become confused and allowed a manifest to be served from a subdirectory. This could cause the appcache to be used to service requests for the top level directory.

References

• Bug 1586630

#CVE-2020-12416: Use-after-free in WebRTC VideoBroadcaster

Reporter

Alex Mayorga

Impact

high

Description

A VideoStreamEncoder may have been freed in a race condition with VideoBroadcaster::AddOrUpdateSink, resulting in a use-after-free, memory corruption, and a potentially exploitable crash.

References

• Bug 1639734

#CVE-2020-12417: Memory corruption due to missing sign-extension for ValueTags on ARM64

Reporter

Deian Stefan

Impact

high

Description

Due to confusion about ValueTags on JavaScript Objects, an object may pass through the type barrier, resulting in memory corruption and a potentially exploitable crash.
Note: this issue only affects Firefox on ARM64 platforms.

References

• Bug 1640737

#CVE-2020-12418: Information disclosure due to manipulated URL object

Reporter

Marcin ‘Icewall’ Noga of Cisco Talos

Impact

high

Description

Manipulating individual parts of a URL object could have caused an out-of-bounds read, leaking process memory to malicious JavaScript.

References

• Bug 1641303

#CVE-2020-12419: Use-after-free in nsGlobalWindowInner

Reporter

worcester12345

Impact

high

Description

When processing callbacks that occurred during window flushing in the parent process, the associated window may die; causing a use-after-free condition. This could have led to memory corruption and a potentially exploitable crash.

References

• Bug 1643874

#CVE-2020-12420: Use-After-Free when trying to connect to a STUN server

Reporter

Byron Campen

Impact

high

Description

When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption and a potentially exploitable crash.

References

• Bug 1643437

#CVE-2020-12402: RSA Key Generation vulnerable to side-channel attack

Reporter

Sohaib ul Hassan, Iaroslav Gridin, Ignacio M. Delgado-Lozano, Cesar Pereida García, Jesús-Javier Chi-Domínguez, Alejandro Cabrera Aldaya, and Billy Bob Brumley, Network and Information Security (NISEC) Group, Tampere University, Finland

Impact

moderate

Description

During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly input-dependent flow. This allowed an attacker able to perform electromagnetic-based side channel attacks to record traces leading to the recovery of the secret primes.
We would like to thank Sohaib ul Hassan for contributing a fix for this issue as well.
Note: An unmodified Firefox browser does not generate RSA keys in normal operation and is not affected, but products built on top of it might.

References

• Bug 1631597

#CVE-2020-12421: Add-On updates did not respect the same certificate trust rules as software updates

Reporter

Chuck Harmston, Robert Hardy

Impact

moderate

Description

When performing add-on updates, certificate chains terminating in non-built-in-roots were rejected (even if they were legitimately added by an administrator.) This could have caused add-ons to become out-of-date silently without notification to the user.

References

• Bug 1308251

#CVE-2020-12422: Integer overflow in nsJPEGEncoder::emptyOutputBuffer

Reporter

Ronald Crane

Impact

moderate

Description

In non-standard configurations, a JPEG image created by JavaScript could have caused an internal variable to overflow, resulting in an out of bounds write, memory corruption, and a potentially exploitable crash.

References

• Bug 1450353

#CVE-2020-12423: DLL Hijacking due to searching %PATH% for a library

Reporter

Riccardo Ancarani

Impact

moderate

Description

When the Windows DLL “webauthn.dll” was missing from the Operating System, and a malicious one was placed in a folder in the user’s %PATH%, Firefox may have loaded the DLL, leading to arbitrary code execution.
Note: This issue only affects the Windows operating system; other operating systems are unaffected.

References

• Bug 1642400

#CVE-2020-12424: WebRTC permission prompt could have been bypassed by a compromised content process

Reporter

Paul Theriault

Impact

low

Description

When constructing a permission prompt for WebRTC, a URI was supplied from the content process. This URI was untrusted, and could have been the URI of an origin that was previously granted permission; bypassing the prompt.

References

• Bug 1562600

#CVE-2020-12425: Out of bound read in Date.parse()

Reporter

Bruno Keith

Impact

low

Description

Due to confusion processing a hyphen character in Date.parse(), a one-byte out of bounds read could have occurred, leading to potential information disclosure.

References

• Bug 1634738

#CVE-2020-12426: Memory safety bugs fixed in Firefox 78

Reporter

Mozilla developers and community

Impact

high

Description

Mozilla developers and community members Bob Clary, Benjamin Bouvier, Calixte Denizet, Christian Holler reported memory safety bugs present in Firefox 77. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 78