Every CVE Search/ Get API key

CVE-2021-3405

A flaw was found in libebml before 1.4.2. A heap overflow bug exists in the implementation of...

6.5 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

1.73%Up 0.7 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 6.5

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.

Record
CVE-2021-3405
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness
CWE-787
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2021-3405
Weakness
CWE-787
Updated
2026-11-02
EUVDEUVD-2021-26733 No score

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.

Record
EUVD-2021-26733
Updated
2026-11-03
GitHub AdvisoriesGHSA-xc72-rxv8-3m23 6.5

A flaw was found in libebml before 1.4.2. A heap overflow bug exists in the implementation of...

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.

Record
GHSA-xc72-rxv8-3m23
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-119, CWE-787
Updated
2026-11-02
OSVALPINE-CVE-2021-3405 6.5

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.

Record
ALPINE-CVE-2021-3405
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-03
OSV 6.5

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.

Record
CVE-2021-3405
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 5 moreShow less
OSVDEBIAN-CVE-2021-3405 6.5

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.

Record
DEBIAN-CVE-2021-3405
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-3405 6.5

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.

Record
UBUNTU-CVE-2021-3405
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVMGASA-2021-0226 No score

Updated libebml packages fix security vulnerabilities

Updated libebml packages fix security vulnerabilities:

Heap use-after-free when parsing malformed file.

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 (CVE-2021-3405).

The mkvtoolnix, libmatroska packages have been rebuilt for the updated libebml.

Record
MGASA-2021-0226
Updated
2026-11-02
OSVMGASA-2021-0338 No score

Updated libebml packages fix a security vulnerability

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 (CVE-2021-3405).

Record
MGASA-2021-0338
Updated
2026-11-02
OSVopenSUSE-SU-2024:10937-1 No score

libebml-devel-1.4.2-2.3 on GA media

These are all security issues fixed in the libebml-devel-1.4.2-2.3 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:10937-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
libebml
Alpine:v3.13
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.14
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.15
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.16
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.17
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.18
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.19
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.20
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.21
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.22
 before 1.4.2-r0
1.4.2-r0
Show 11 moreShow less
Affected packages
PackageAffectedFixed
libebml
Alpine:v3.23
 before 1.4.2-r0
1.4.2-r0
libebml
Alpine:v3.24
 before 1.4.2-r0
1.4.2-r0
libebml
Debian:12
 before 1.4.2-1
1.4.2-1
libebml
Debian:13
 before 1.4.2-1
1.4.2-1
libebml
Debian:14
 before 1.4.2-1
1.4.2-1
libebml
Debian:9
 before 1.3.4-1+deb9u2, plus listed versions
1.3.4-11.3.4-1+deb9u1
1.3.4-1+deb9u2
libebml
Mageia:7
 before 1.4.2-1.mga7
1.4.2-1.mga7
mkvtoolnix
Mageia:7
 before 32.0.0-2.1.mga7
32.0.0-2.1.mga7
libmatroska
Mageia:7
 before 1.5.0-2.1.mga7
1.5.0-2.1.mga7
libebml
Mageia:8
 before 1.4.2-1.mga8
1.4.2-1.mga8
libebml
Ubuntu:25.10
 All versions, plus listed versions
1.4.5-1
 None known

History

History
RecordedChangedSources
affected, aliases, referencesOSV
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-3405 is a medium vulnerability (CVSS 6.5) in Matroska Libebml, published February 23, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.73%, the 77th percentile. Fixed in libebml 1.4.2-r0.

References

Show 18 moreShow less
Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open