// For flags

CVE-2021-29157

Ubuntu Security Notice USN-4993-1

Severity Score

5.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Dovecot before 2.3.15 allows ../ Path Traversal. An attacker with access to the local filesystem can trick OAuth2 authentication into using an HS256 validation key from an attacker-controlled location. This occurs during use of local JWT validation with the posix fs driver.

Dovecot versiones anteriores a 2.3.15, permite un Salto de Ruta ../. Un atacante con acceso al sistema de archivos local puede engañar a la autenticación OAuth2 en usar una clave de comprobación HS256 desde una ubicación controlada por el atacante. Esto ocurre durante el uso de la comprobación JWT local con el controlador posix fs

Kirin discovered that Dovecot incorrectly escaped kid and azp fields in JWT tokens. A local attacker could possibly use this issue to validate tokens using arbitrary keys. This issue only affected Ubuntu 20.10 and Ubuntu 21.04. Fabian Ising and Damian Poddebniak discovered that Dovecot incorrectly handled STARTTLS when using the SMTP submission service. A remote attacker could possibly use this issue to inject plaintext commands before STARTTLS negotiation. Various other issues were also addressed.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-03-25 CVE Reserved
  • 2021-06-21 CVE Published
  • 2024-08-03 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Dovecot
Search vendor "Dovecot"
 Dovecot
Search vendor "Dovecot" for product "Dovecot"
 >= 2.3.11 < 2.3.14.1
Search vendor "Dovecot" for product "Dovecot" and version " >= 2.3.11 < 2.3.14.1"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected