CVE-2021-3405

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

1.74% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 75.7% of scored records. A rank, not a probability.

NVD base score

6.5 (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:N/I:N/A:H

NVD analysis status

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

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

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

2021-02-23 19:05Z5 YR AGO

Last updated

2024-08-03 16:53Z2 YR AGO

Reserved

2021-02-09

Assigning CNA

redhat

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

Data version

5.1

Document digest

702b8f8f593b44276c7cb58471c7b54f595626403e2b77ee5c896496021207d5

• github.comhttps://github.com/Matroska-Org/libebml/issues/74x_refsource_MISC
• lists.fedoraproject.orgFEDORA-2021-9a0fff8455https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YY7R2JZRO5I6WS62KTJFTZGKYELVFTVB/vendor-advisoryx_refsource_FEDORA
• lists.fedoraproject.orgFEDORA-2021-aa78f97893https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JNHQI6MDOECJ2HT5GCLEX2DMJFEOWPW7/vendor-advisoryx_refsource_FEDORA
• lists.fedoraproject.orgFEDORA-2021-e283997bb9https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHIIMWZKHHELFF4NRDMOOCS3HKK3K4DF/vendor-advisoryx_refsource_FEDORA
• lists.debian.org[debian-lts-announce] 20210418 [SECURITY] [DLA 2629-1] libebml security updatehttps://lists.debian.org/debian-lts-announce/2021/04/msg00016.htmlmailing-listx_refsource_MLIST
• security.gentoo.orgGLSA-202208-21https://security.gentoo.org/glsa/202208-21vendor-advisoryx_refsource_GENTOO