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Firefox Privacy Notice

Mozilla Foundation Security Advisory 2021-08

Security Vulnerabilities fixed in Firefox ESR 78.8

Announced
February 23, 2021
Impact
high
Products
Firefox ESR
Fixed in
  • Firefox ESR 78.8

#CVE-2021-23969: Content Security Policy violation report could have contained the destination of a redirect

Reporter
Masato Kinugawa
Impact
high
Description

As specified in the W3C Content Security Policy draft, when creating a violation report, "User agents need to ensure that the source file is the URL requested by the page, pre-redirects. If that’s not possible, user agents need to strip the URL down to an origin to avoid unintentional leakage." Under certain types of redirects, Firefox incorrectly set the source file to be the destination of the redirects. This was fixed to be the redirect destination's origin.

References

#CVE-2021-23968: Content Security Policy violation report could have contained the destination of a redirect

Reporter
Ademar Nowasky Junior
Impact
high
Description

If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs.

References

#CVE-2021-23973: MediaError message property could have leaked information about cross-origin resources

Reporter
Andreas Pehrson
Impact
low
Description

When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of that error may have revealed information about the resource.

References

#CVE-2021-23978: Memory safety bugs fixed in Firefox 86 and Firefox ESR 78.8

Reporter
Mozilla developers
Impact
high
Description

Mozilla developers Alexis Beingessner, Tyson Smith, Nika Layzell, and Mats Palmgren reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. 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