Out-of-bounds Read in Microsoft Windows

CVE-2021-29964

A locally-installed hostile program could send `WM_COPYDATA` messages that Firefox would process incorrectly, leading to an out-of-bounds read. *This bug only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 78.11, Firefox < 89, and Firefox ESR < 78.11.

Vulnerability class: Buffer Overflow

EPSS: 0.008 (52.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-29964?
CVE-2021-29964 is a high-severity vulnerability in Microsoft Windows, classified under Out-of-bounds Read. CVSS score: 7.1/10. Published 2021-06-24.
How severe is CVE-2021-29964?
High severity. CVSS v3 base score is 7.1 out of 10.
Is CVE-2021-29964 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.