CVE-2021-23978

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

1.53% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 74.2% of scored records. A rank, not a probability.

NVD base score

8.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-02-26 15:28Z5 YR AGO

Last updated

2024-08-03 19:14Z2 YR AGO

Reserved

2021-01-13

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-787Out-of-bounds WriteBase
• CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')Base

Data version

5.1

Document digest

768e32d90a83255248d10a28e97d5171059e0c3e62019afde59c4b5bcac40ea4

• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-07/x_refsource_MISC
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-09/x_refsource_MISC
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-08/x_refsource_MISC
• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/buglist.cgi?bug_id=786797%2C1682928%2C1687391%2C1687597x_refsource_MISC
• lists.debian.org[debian-lts-announce] 20210301 [SECURITY] [DLA 2578-1] thunderbird security updatehttps://lists.debian.org/debian-lts-announce/2021/03/msg00000.htmlmailing-listx_refsource_MLIST
• www.debian.orgDSA-4866https://www.debian.org/security/2021/dsa-4866vendor-advisoryx_refsource_DEBIAN
• security.gentoo.orgGLSA-202104-10https://security.gentoo.org/glsa/202104-10vendor-advisoryx_refsource_GENTOO
• security.gentoo.orgGLSA-202104-09https://security.gentoo.org/glsa/202104-09vendor-advisoryx_refsource_GENTOO