CVE-2021-3405
A flaw was found in libebml before 1.4.2. A heap overflow bug exists in the implementation of EbmlString::ReadData and EbmlUnicodeString::ReadData in libebml.
02 Description
A flaw was found in libebml before 1.4.2. A heap overflow bug exists in the implementation of EbmlString::ReadData and EbmlUnicodeString::ReadData in libebml.
03 Exploitation and scoring
- 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
- 1.72% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 77.4% 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.
04 Metadata
- 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
05 Affected products
06 References
- github.comhttps://github.com/Matroska-Org/libebml/issues/74
- lists.fedoraproject.orgFEDORA-2021-9a0fff8455https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YY7R2JZRO5I6WS62KTJFTZGKYELVFTVB/
- lists.fedoraproject.orgFEDORA-2021-aa78f97893https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JNHQI6MDOECJ2HT5GCLEX2DMJFEOWPW7/
- lists.fedoraproject.orgFEDORA-2021-e283997bb9https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHIIMWZKHHELFF4NRDMOOCS3HKK3K4DF/
- lists.debian.org[debian-lts-announce] 20210418 [SECURITY] [DLA 2629-1] libebml security updatehttps://lists.debian.org/debian-lts-announce/2021/04/msg00016.html
- security.gentoo.orgGLSA-202208-21https://security.gentoo.org/glsa/202208-21
07 Fixed in
Arch Linux
- libebml Fixed in 1.4.2-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
Debian 12
- libebml Fixed in 1.4.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- libebml Fixed in 1.4.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- libebml Fixed in 1.4.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 25.10
- libebml No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.