CVE-2021-3405: debian debian_linux Out-of-bounds Write
Vulnerability summary
CVE-2021-3405 is a medium (CVSS 6.5) Out-of-bounds Write vulnerability in debian debian_linux. EPSS estimates a 1.73% chance of exploitation in the next 30 days, higher than 77.6% of scored vulnerabilities. 1 public exploit is recorded.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Timeline
- 23-02-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- OSV · AlpineEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS trend
Probability
1.73%
Chance of exploitation in the next 30 days
Percentile
78%
Versus all other CVEs
30-day change
Decrease -0.01 pp
From 1.74% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundLibebml
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Mageia4 products
- libebml< 1.4.2-1.mga7
- libmatroska< 1.5.0-2.1.mga7
- mkvtoolnix< 32.0.0-2.1.mga7
- libebml< 1.4.2-1.mga8
Debian2 products
- libebml< 1.3.4-1+deb9u2 | < 1.4.2-1
- debian_linuxEOL9.0
Alpine1 product
- libebml< 1.4.2-r0
Fedoraproject1 product
- fedoraEOL32 | 33 | 34
Matroska1 product
- libebml< 1.4.2
Ubuntu1 product
- libebmlAll versions (No fix recorded)
6 vendors · 10 products
References
18 links- github.com/Matroska-Org/libebml/issues/74X Refsource MISCREPORTExploitIssue TrackingThird Party Advisory
lists.debian.org/debian-lts-announce/2021/04/msg00016.htmlMailing ListX Refsource MLISTThird Party Advisory