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Mozilla Foundation Security Advisory 2021-34

Security Vulnerabilities fixed in Firefox ESR 78.13

Announced
August 10, 2021
Impact
high
Products
Firefox ESR
Fixed in
  • Firefox ESR 78.13

#CVE-2021-29986: Race condition when resolving DNS names could have led to memory corruption

Reporter
pahhur
Impact
high
Description

A suspected race condition when calling getaddrinfo led to memory corruption and a potentially exploitable crash.
Note: This issue only affected Linux operating systems. Other operating systems are unaffected.

References

#CVE-2021-29988: Memory corruption as a result of incorrect style treatment

Reporter
Irvan Kurniawan
Impact
high
Description

Firefox incorrectly treated an inline list-item element as a block element, resulting in an out of bounds read or memory corruption, and a potentially exploitable crash.

References

#CVE-2021-29984: Incorrect instruction reordering during JIT optimization

Reporter
Lukas Bernhard
Impact
high
Description

Instruction reordering resulted in a sequence of instructions that would cause an object to be incorrectly considered during garbage collection. This led to memory corruption and a potentially exploitable crash.

References

#CVE-2021-29980: Uninitialized memory in a canvas object could have led to memory corruption

Reporter
Irvan Kurniawan
Impact
high
Description

Uninitialized memory in a canvas object could have caused an incorrect free() leading to memory corruption and a potentially exploitable crash.

References

#CVE-2021-29985: Use-after-free media channels

Reporter
Marcin 'Icewall' Noga of Cisco Talos
Impact
moderate
Description

A use-after-free vulnerability in media channels could have led to memory corruption and a potentially exploitable crash.

References

#CVE-2021-29989: Memory safety bugs fixed in Firefox 91 and Firefox ESR 78.13

Reporter
Mozilla developers and community
Impact
high
Description

Mozilla developers Christoph Kerschbaumer, Simon Giesecke, Sandor Molnar, and Olli Pettay reported memory safety bugs present in Firefox 90 and Firefox ESR 78.12. 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