CVE-2020-26972

The lifecycle of IPC Actors allows managed actors to outlive their manager actors; and the former must ensure that they are not attempting to use a dead actor they have a reference to. Such a check was omitted in WebGL, resulting in a use-after-free and a potentially exploitable crash. This vulnerability affects Firefox < 84.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1671382
• https://www.mozilla.org/security/advisories/mfsa2020-54/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1671382
• https://www.mozilla.org/security/advisories/mfsa2020-54/