Every CVE Search/ Get API key

CVE-2025-59028

When sending invalid base64 SASL data, login process is disconnected from the auth server,...

5.3 MediumFix available

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.46%Up 0.4 points since Mar 27, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
CVE-2025-59028
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-20
Updated
2026-11-02
EUVDEUVD-2025-209088 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
EUVD-2025-209088
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
GitHub AdvisoriesGHSA-9q9x-wwfr-fxqm 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server,...

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
GHSA-9q9x-wwfr-fxqm
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-20
Updated
2026-11-02
NVD 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
CVE-2025-59028
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-20
Updated
2026-11-02
OSVALPINE-CVE-2025-59028 7.5

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
ALPINE-CVE-2025-59028
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSV 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
CVE-2025-59028
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-20
Updated
2026-11-02
Show 8 moreShow less
OSVDEBIAN-CVE-2025-59028 7.5

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
DEBIAN-CVE-2025-59028
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2025-59028 5.3

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
UBUNTU-CVE-2025-59028
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVAZL-81686 No score

CVE-2025-59028 affecting package dovecot 2.3.20-1

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Record
AZL-81686
Updated
2026-11-05
OSVopenSUSE-SU-2026:10442-1 No score

dovecot24-2.4.3-1.1 on GA media

These are all security issues fixed in the dovecot24-2.4.3-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:10442-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:20554-1 No score

Security update for dovecot24

This update for dovecot24 fixes the following issues:

  • Update to v2.4.3
  • CVE-2025-59028: Invalid base64 authentication can cause DoS for other logins (bsc#1260894).
  • CVE-2025-59031: decode2text.sh OOXML extraction may follow symlinks and read unintended files during indexing (bsc#1260895).
  • CVE-2025-59032: pigeonhole: ManageSieve panic occurs with sieve-connect as a client (bsc#1260902).
  • CVE-2026-24031: SQL injection possible if auth_username_chars is configured empty. Fixed escaping to always happen. v2.4 regression (bsc#1260896).
  • CVE-2026-27855: OTP driver vulnerable to replay attack (bsc#1260900).
  • CVE-2026-27856: Doveadm credentials were not checked using timing-safe checking function (bsc#1260899).
  • CVE-2026-27857: sending excessive parenthesis causes imap-login to use excessive memory (bsc#1260898).
  • CVE-2026-27858: pigeonhole: managesieve-login can allocate large amount of memory during authentication (bsc#1260901).
  • CVE-2026-27859: excessive RFC 2231 MIME parameters in email would can excessive CPU usage (bsc#1260897).
  • CVE-2026-27860: LDAP query injection possible if auth_username_chars is configured empty. Fixed escaping to always happen. v2.4 regression (bsc#1260893).
Record
openSUSE-SU-2026:20554-1
Updated
2026-11-02
OSVSUSE-SU-2026:21208-1 No score

Security update for dovecot24

This update for dovecot24 fixes the following issues:

  • Update to v2.4.3
  • CVE-2025-59028: Invalid base64 authentication can cause DoS for other logins (bsc#1260894).
  • CVE-2025-59031: decode2text.sh OOXML extraction may follow symlinks and read unintended files during indexing (bsc#1260895).
  • CVE-2025-59032: pigeonhole: ManageSieve panic occurs with sieve-connect as a client (bsc#1260902).
  • CVE-2026-24031: SQL injection possible if auth_username_chars is configured empty. Fixed escaping to always happen. v2.4 regression (bsc#1260896).
  • CVE-2026-27855: OTP driver vulnerable to replay attack (bsc#1260900).
  • CVE-2026-27856: Doveadm credentials were not checked using timing-safe checking function (bsc#1260899).
  • CVE-2026-27857: sending excessive parenthesis causes imap-login to use excessive memory (bsc#1260898).
  • CVE-2026-27858: pigeonhole: managesieve-login can allocate large amount of memory during authentication (bsc#1260901).
  • CVE-2026-27859: excessive RFC 2231 MIME parameters in email would can excessive CPU usage (bsc#1260897).
  • CVE-2026-27860: LDAP query injection possible if auth_username_chars is configured empty. Fixed escaping to always happen. v2.4 regression (bsc#1260893).
Record
SUSE-SU-2026:21208-1
Updated
2026-11-02
OSVSUSE-SU-2026:4139-1 No score

Security update for dovecot23

This update for dovecot23 fixes the following issues:

  • CVE-2024-23184: parsing of messages containing many address headers (From, To, Cc, Bcc, etc.) could be excessively CPU intensive (bsc#1229184).
  • CVE-2024-23185: large headers can cause resource exhaustion when parsing message (bsc#1229183).
  • CVE-2025-59028: Invalid base64 authentication can cause DoS for other logins (bsc#1260894).
  • CVE-2025-59031: decode2text.sh OOXML extraction may follow symlinks and read unintended files during indexing (bsc#1260895).
  • CVE-2025-59032: pigeonhole: ManageSieve panic occurs with sieve-connect as a client (bsc#1260902).
  • CVE-2026-27852: DoS by sending mail with bad header (bsc#1276799).
  • CVE-2026-27855: OTP driver vulnerable to replay attack (bsc#1260900).
  • CVE-2026-27856: Doveadm credentials were not checked using timing-safe checking function (bsc#1260899).
  • CVE-2026-27857: sending excessive parenthesis causes imap-login to use excessive memory (bsc#1260898).
  • CVE-2026-27858: pigeonhole: managesieve-login can allocate large amount of memory during authentication (bsc#1260901).
  • CVE-2026-27859: excessive RFC 2231 MIME parameters in email would can excessive CPU usage (bsc#1260897).
  • CVE-2026-33263: submission-login: Panic when mail_max_userip_connections is reached (bsc#1276794).
  • CVE-2026-33603: login: base64 input can contain tabs that bypass IPC protection (bsc#1265147).
  • CVE-2026-33604: SMTP Smuggling via Missing Dot-Stuffing (bsc#1276802).
  • CVE-2026-33605: managesieve-login: Pre-auth crash (bsc#1276809).
  • CVE-2026-33606: dsync: Mail content can cause dsync protocol injection (bsc#1276800).
  • CVE-2026-33607: IMAP LIST match_sub() Exponential Backtracking -- CPU Denial of Service (bsc#1276795).
  • CVE-2026-40014: CPU DoS via Crafted References Header (bsc#1276804).
  • CVE-2026-40015: imap-hibernate can be crashed (bsc#1276812).
  • CVE-2026-40016: Sieve :contains/:matches O(NxM) substring match bypasses sieve_max_cpu_time limit (bsc#1265148).
  • CVE-2026-40019: managesieve-login pre-auth infinite loop (bsc#1276811).
  • CVE-2026-40020: IMAP folders can be shared-spammed to everyone (bsc#1265149).
  • CVE-2026-40203: IMAP Compression Can Reveal Whether a Small Synced Email Body Matches Sender-Chosen Text (bsc#1276815).
  • CVE-2026-40205: OAuth2 passdb scope enforcement bypass via OR semantics in remote validation path (bsc#1276820).
  • CVE-2026-42006: imap-login: uncontrolled memory usage with excessive bracing over IMAP (bsc#1265150).
  • CVE-2026-42007: editheader RCE (bsc#1276817).
  • CVE-2026-42008: XCLIENT FORWARD= bare token not namespaced (bsc#1276824).
  • CVE-2026-42391: imap: Pre-login memory/CPU growth with ID command (bsc#1276835).
  • CVE-2026-42393: doveadm_password or api key length can still be leaked with timing comparisons (bsc#1276827).
  • CVE-2026-42395: Single NUL-Byte XCLIENT FORWARD Payload Crashes (bsc#1276826).
  • CVE-2026-52681: Sieve resource usage tracking lost when active script changes (bsc#1276828).
  • CVE-2026-52687: IMAP: COMPRESS ZSTD can cause excessive memory usage (bsc#1276837).
  • CVE-2026-73208: auth: db-oauth2: aud claim used as fallback for missing scope claim (bsc#1276830).
  • CVE-2026-73209: imap-login crash: Self-recursion on zero-output decompress chunks (bsc#1276833).

Changes for dovecot23:

  • Update to version 2.3.21.1.
Record
SUSE-SU-2026:4139-1
Updated
2026-11-02
OSVUSN-8136-1 No score

dovecot vulnerabilities

It was discovered that Dovecot incorrectly handled invalid base64 SASL data. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 25.10. (CVE-2025-59028)

It was discovered that Dovecot script decode2text.sh incorrectly handled zip files. An attacker could possibly use this issue to obtain sensitive information. (CVE-2025-59031)

It was discovered that Dovecot incorrectly handled certain AUTHENTICATE requests. An attacker could possibly use this issue to cause a denial of service. (CVE-2025-59032)

It was discovered that Dovecot incorrectly handled certain SQL based authentication. An attacker could possibly use this issue to bypass authentication. This issue only affected Ubuntu 25.10. (CVE-2026-24031)

It was discovered that Dovecot incorrectly handled certain LDAP based authentication. An attacker could possibly use this issue to bypass restrictions and allow probing of LDAP structure. This issue only affected Ubuntu 25.10. (CVE-2026-27860)

It was discovered that Dovecot is vulnerable to replay attack under certain conditions. An attacker could possibly use this issue to bypass authentication. (CVE-2026-27855)

It was discovered that Dovecot is vulnerable to a timing attack under certain conditions. An attacker could possibly use this issue to bypass authentication. (CVE-2026-27856)

It was discovered that Dovecot incorrectly handled certain IMAP login requests. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-27857)

It was discovered that Dovecot incorrectly handled certain specially crafted messages. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-27858)

It was discovered that Dovecot incorrectly handled certain specially crafted mail messages. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-27859)

It was discovered that Dovecot incorrectly handles file paths. A attacker could possibly use this issue to perform a path traversal and obtain or modify arbitrary files. This issue only affected Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2026-0394)

Record
USN-8136-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
dovecot
Alpine:v3.23
 before 2.4.3-r0
2.4.3-r0
dovecot
Alpine:v3.24
 before 2.4.3-r0
2.4.3-r0
dovecot
Azure Linux:3
 through 2.3.20-1 None known
dovecot
Debian:13
 before 1:2.4.1+dfsg1-6+deb13u4, plus listed versions
1:2.4.1+dfsg1-61:2.4.1+dfsg1-6+deb13u11:2.4.1+dfsg1-6+deb13u21:2.4.1+dfsg1-6+deb13u3
1:2.4.1+dfsg1-6+deb13u4
dovecot
Debian:14
 before 1:2.4.3+dfsg1-1, plus listed versions
1:2.4.1+dfsg1-61:2.4.1+dfsg1-71:2.4.1+dfsg1-81:2.4.1+dfsg1-91:2.4.2+dfsg1-11:2.4.2+dfsg1-21:2.4.2+dfsg1-31:2.4.2+dfsg1-4
1:2.4.3+dfsg1-1
dovecot24
SUSE:Linux Enterprise Server 16.0
From an advisory covering 10 CVEs
 before 2.4.3-160000.1.1
2.4.3-160000.1.1
dovecot24
SUSE:Linux Enterprise Server for SAP applications 16.0
From an advisory covering 10 CVEs
 before 2.4.3-160000.1.1
2.4.3-160000.1.1
dovecot23
SUSE:Linux Enterprise Module for Server Applications 15 SP7
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
Show 13 moreShow less
Affected packages
PackageAffectedFixed
dovecot23
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server 15 SP4-LTSS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server 15 SP5-LTSS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server 15 SP6-LTSS
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server for SAP Applications 15 SP4
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server for SAP Applications 15 SP5
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot23
SUSE:Linux Enterprise Server for SAP Applications 15 SP6
From an advisory covering 34 CVEs
 before 2.3.21.1-150200.76.1
2.3.21.1-150200.76.1
dovecot
Ubuntu:25.10
 before 1:2.4.1+dfsg1-5ubuntu4.1, plus listed versions
1:2.3.21.1+dfsg1-1ubuntu21:2.4.1+dfsg1-5ubuntu11:2.4.1+dfsg1-5ubuntu31:2.4.1+dfsg1-5ubuntu4
1:2.4.1+dfsg1-5ubuntu4.1
dovecot
Ubuntu:22.04:LTS
 before 1:2.3.16+dfsg1-3ubuntu2.7, plus listed versions
1:2.3.13+dfsg1-1ubuntu31:2.3.16+dfsg1-3ubuntu11:2.3.16+dfsg1-3ubuntu21:2.3.16+dfsg1-3ubuntu2.11:2.3.16+dfsg1-3ubuntu2.21:2.3.16+dfsg1-3ubuntu2.41:2.3.16+dfsg1-3ubuntu2.6
1:2.3.16+dfsg1-3ubuntu2.7
dovecot
Ubuntu:24.04:LTS
 before 1:2.3.21+dfsg1-2ubuntu6.3, plus listed versions
1:2.3.20+dfsg1-1ubuntu31:2.3.21+dfsg1-2ubuntu11:2.3.21+dfsg1-2ubuntu21:2.3.21+dfsg1-2ubuntu41:2.3.21+dfsg1-2ubuntu51:2.3.21+dfsg1-2ubuntu61:2.3.21+dfsg1-2ubuntu6.11:2.3.21+dfsg1-2ubuntu6.2
1:2.3.21+dfsg1-2ubuntu6.3
dovecot24
openSUSE:Tumbleweed
From an advisory covering 10 CVEs
 before 2.4.3-1.1
2.4.3-1.1
dovecot24
openSUSE:Leap 16.0
From an advisory covering 10 CVEs
 before 2.4.3-160000.1.1
2.4.3-160000.1.1

History

History
RecordedChangedSources
affected
factsOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

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

In short

CVE-2025-59028 is a medium vulnerability (CVSS 5.3) in Dovecot, published March 27, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.46%, the 40th percentile. Fixed in dovecot 2.4.3-r0.

References

Show 87 moreShow less
Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open