Mozilla Foundation Security Advisory 2021-10

Security Vulnerabilities fixed in Firefox 87

Announced
March 23, 2021
Impact
high
Products
Firefox
Fixed in
  • Firefox 87

Note: This advisory was updated May 3, 2021 to include CVE-2021-29951 and again on June 8, 2021 to include CVE-2021-29955 - both were also fixed in this release.

#CVE-2021-29955: Transient Execution Vulnerability allowed leaking arbitrary memory address

Reporter
Hany Ragab, Enrico Barberis, Herbert Bos, and Cristiano Giuffrida from the VUSec group at VU Amsterdam
Impact
high
Description

A transient execution vulnerability, named Floating Point Value Injection (FPVI) allowed an attacker to leak arbitrary memory addresses and may have also enabled JIT type confusion attacks. (A related vulnerability, Speculative Code Store Bypass (SCSB), did not affect Firefox.)

References

#CVE-2021-23981: Texture upload into an unbound backing buffer resulted in an out-of-bound read

Reporter
Abraruddin Khan and Omair
Impact
high
Description

A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it, resulting in memory corruption and a potentially exploitable information leak or crash.

References

#CVE-2021-29951: Mozilla Maintenance Service could have been started or stopped by domain users

Reporter
James Forshaw
Impact
moderate
Description

The Mozilla Maintenance Service granted SERVICE_START access to BUILTIN|Users which, in a domain network, grants normal remote users access to start or stop the service. This could be used to prevent the browser update service from operating (if an attacker spammed the 'Stop' command); but also exposed attack surface in the maintenance service.
Note: This issue only affected Windows operating systems older than Win 10 build 1709. Other operating systems are unaffected.

References

#CVE-2021-23982: Internal network hosts could have been probed by a malicious webpage

Reporter
Samy Kamkar, Ben Seri, and Gregory Vishnepolsky
Impact
moderate
Description

Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections.

References

#CVE-2021-23983: Transitions for invalid ::marker properties resulted in memory corruption

Reporter
Irvan Kurniawan
Impact
moderate
Description

By causing a transition on a parent node by removing a CSS rule, an invalid property for a marker could have been applied, resulting in memory corruption and a potentially exploitable crash.

References

#CVE-2021-23984: Malicious extensions could have spoofed popup information

Reporter
Rob Wu
Impact
moderate
Description

A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials.

References

#CVE-2021-23985: Devtools remote debugging feature could have been enabled without indication to the user

Reporter
Anonymous working with Trend Micro's Zero Day Initiative
Impact
low
Description

If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote debugging feature could have been enabled in a way that was unnoticable to the user. This would have allowed a remote attacker (able to make a direct network connection to the victim) to monitor the user's browsing activity and (plaintext) network traffic. This was addressed by providing a visual cue when Devtools has an open network socket.

References

#CVE-2021-23986: A malicious extension could have performed credential-less same origin policy violations

Reporter
Armin Razmjou
Impact
low
Description

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication.

References

#CVE-2021-23987: Memory safety bugs fixed in Firefox 87 and Firefox ESR 78.9

Reporter
Mozilla developers and community
Impact
high
Description

Mozilla developers and community members Matthew Gregan, Tyson Smith, Julien Wajsberg, and Alexis Beingessner reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. 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

#CVE-2021-23988: Memory safety bugs fixed in Firefox 87

Reporter
Mozilla developers and community
Impact
moderate
Description

Mozilla developers Tyson Smith and Christian Holler reported memory safety bugs present in Firefox 86. 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