7.4

CVE-2021-3618: debian debian_linux Improper Certificate Validation

CVSS: 7.4v3.1HighModified
AliasesALPINE-CVE-2021-3618MGASA-2021-0540SUSE-RU-2022:0655-1
Published 23-03-2022Last modified 03-08-2024
Open JSON

Vulnerability summary

CVE-2021-3618 is a high (CVSS 7.4) Improper Certificate Validation vulnerability in debian debian_linux. EPSS estimates a 2.03% chance of exploitation in the next 30 days, higher than 80.7% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.4/10
010
High · v3.1 (NVD)
EPSS score
2.03%
0%100%
Low · -0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 1
DLA-3203-1USN-5371-1

Timeline

  1. 23-03-2022
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

Description

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

2.03%

Chance of exploitation in the next 30 days

Percentile

81%

Versus all other CVEs

30-day change

-0.01 pp

From 2.04% on 20-09-2026

20-09-202620-10-2026
EPSS score
2.03%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Suse43 products
  • nginx&distro=SUSE Enterprise Storage 6< 1.16.1-150100.6.16.1
  • nginx&distro=SUSE Enterprise Storage 7< 1.16.1-150200.3.9.1
  • nginx&distro=SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS< 1.16.1-150100.6.16.1
  • nginx&distro=SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS< 1.16.1-150100.6.16.1
  • nginx&distro=SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS< 1.16.1-150200.3.9.1
Debian4 products
  • nginx< 1.20.2-2
  • sendmail< 8.16.1-2
  • vsftpdAll versions (No fix recorded) | < 3.0.5-0.1
  • debian_linuxEOL10.0
Opensuse4 products
  • nginx&distro=openSUSE Leap 15.3< 1.19.8-150300.3.9.1
  • nginx&distro=openSUSE Leap 15.4< 1.19.8-150300.3.9.1
  • vsftpd&distro=openSUSE Leap 15.3< 3.0.5-150200.12.9.1
  • vsftpd&distro=openSUSE Leap 15.4< 3.0.5-150400.3.3.1
Ubuntu3 products
  • nginx< 1.18.0-6ubuntu14.1 | All versions (No fix recorded) | < 1.10.3-0ubuntu0.16.04.5+esm3 | < 1.14.0-0ubuntu1.10 | < 1.18.0-0ubuntu1.3
  • sendmailAll versions (No fix recorded)
  • vsftpd< 3.0.5-0ubuntu0.20.04.1 | All versions (No fix recorded)
Mageia2 products
  • nginx< 1.18.0-5.2.mga8
  • vsftpd< 3.0.5-1.mga8
Alpine1 product
  • nginx< 1.20.1-r1
F51 product
Fedoraproject1 product
Sendmail1 product
Vsftpd_project1 product

10 vendors · 61 products

References

46 links
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