CVE-2021-43539

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

1.62% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 73.9% 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

2021-12-08 21:20Z4 YR AGO

Last updated

2024-08-04 04:03Z2 YR AGO

Reserved

2021-11-08

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-416Use After FreeVariant

Data version

5.1

Document digest

1847e4145e25341534efb5b6010c79c1ec4256696a9976679b618bf591fb16b9

• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-53/x_refsource_MISC
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-54/x_refsource_MISC
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-52/x_refsource_MISC
• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1739683x_refsource_MISC
• www.debian.orgDSA-5026https://www.debian.org/security/2021/dsa-5026vendor-advisoryx_refsource_DEBIAN
• lists.debian.org[debian-lts-announce] 20211229 [SECURITY] [DLA 2863-1] firefox-esr security updatehttps://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlmailing-listx_refsource_MLIST
• www.debian.orgDSA-5034https://www.debian.org/security/2022/dsa-5034vendor-advisoryx_refsource_DEBIAN
• lists.debian.org[debian-lts-announce] 20220104 [SECURITY] [DLA 2874-1] thunderbird security updatehttps://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlmailing-listx_refsource_MLIST
• security.gentoo.orgGLSA-202202-03https://security.gentoo.org/glsa/202202-03vendor-advisoryx_refsource_GENTOO
• security.gentoo.orgGLSA-202208-14https://security.gentoo.org/glsa/202208-14vendor-advisoryx_refsource_GENTOO