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CVE-2021-29980

27
FAUCET Score

CVE-2021-29980 describes a memory corruption vulnerability in Mozilla Firefox and Thunderbird, affecting versions prior to 91 and 78.13 respectively. This flaw, caused by uninitialized memory in a canvas object, could lead to an incorrect free() operation, resulting in a potentially exploitable crash. Rated with a CVSS score of 8.8 (High), it presents a significant risk due to its network-based attack vector and high impact on confidentiality, integrity, and availability, though user interaction is required. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 91.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 78.13.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
< 78.13.0CPE matchmatch criteria
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.41%
Probability of exploitation in next 30 days
EPSS Percentile
69.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0141 is in the 69th percentile among its peer group of 14,848 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (9)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: thunderbird-0:78.13.0-1.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:78.13.0-2.el7_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: thunderbird-0:78.13.0-1.el7_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: thunderbird-0:78.13.0-1.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: firefox-0:78.13.0-2.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Extended Update SupportFixed in: firefox-0:78.13.0-2.el8_1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Extended Update SupportFixed in: thunderbird-0:78.13.0-1.el8_1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: firefox-0:78.13.0-2.el8_2
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2021-29980Important

Mozilla: Uninitialized memory in a canvas object could have led to memory corruption

Aug 10, 2021

References

bugzilla.mozilla.org / show_bug.cgi
ExploitIssue TrackingVendor Advisory
security.gentoo.org / glsa/202202-03
Third Party Advisory
security.gentoo.org / glsa/202208-14
Third Party Advisory
mozilla.org / security/advisories/mfsa2021-33
Vendor Advisory
mozilla.org / security/advisories/mfsa2021-34
Vendor Advisory
mozilla.org / security/advisories/mfsa2021-35
Vendor Advisory
mozilla.org / security/advisories/mfsa2021-36
Vendor Advisory