Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.

The CentOS Linux 7 host has packages installed that are affected by a vulnerability as referenced in the TuxCare CENTOS7:CLSA-2026:1790640190 advisory.

  - Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16. (CVE-2021-33582)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Rocky Linux 8 host has packages installed that are affected by a vulnerability as referenced in the CIQ crlsa-2021_3492 advisory.

    * cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

Tenable has extracted the preceding description block directly from the CIQ security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 8 host has packages installed that are affected by a vulnerability as referenced in the AXSA:2021-2426:03 advisory.

    * cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16. (CVE-2021-33582)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2022:0245 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

      CVE-2021-33582:
      Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon     hang) via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2021:0067 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2019-18928:
    Cyrus IMAP 2.5.x before 2.5.14 and 3.x before 3.0.12 allows privilege escalation because an HTTP request     may be interpreted in the authentication context of an unrelated previous request that arrived over the     same connection.

    CVE-2019-19783:
    An issue was discovered in Cyrus IMAP before 2.5.15, 3.0.x before 3.0.13, and 3.1.x through 3.1.8. If     sieve script uploading is allowed (3.x) or certain non-default sieve options are enabled (2.x), a user     with a mail account on the service can use a sieve script containing a fileinto directive to create any     mailbox with administrator privileges, because of folder mishandling in autosieve_createfolder() in     imap/lmtp_sieve.c.

    CVE-2021-33582:
    Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-7224-1 advisory.

    It was discovered that non-authentication-related HTTP requests could be interpreted in an authentication     context by a Cyrus IMAP Server when multiple requests arrived over the same connection. An unauthenticated     attacker could possibly use this issue to perform a privilege escalation attack. This issue only affected     Ubuntu 18.04 LTS. (CVE-2019-18928)

    Matthew Horsfall discovered that Cyrus IMAP Server utilized a poor string hashing algorithm that could be     abused to control where data was being stored. An attacker could possibly use this issue to perform a     denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2021-33582)

    Damian Poddebniak discovered that Cyrus IMAP Server could interpret specially crafted commands to exploit     a memory issue. An authenticated attacker could possibly use this issue to perform a denial of service.
    This issue only affected Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2024-34055)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote CentOS Linux 9 host has packages installed that are affected by a vulnerability as referenced in the cyrus- imapd-3.4.1-6.el9 build changelog.

  - Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16. (CVE-2021-33582)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Debian 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3052 advisory.

  - Cyrus IMAP 2.5.x before 2.5.14 and 3.x before 3.0.12 allows privilege escalation because an HTTP request     may be interpreted in the authentication context of an unrelated previous request that arrived over the     same connection. (CVE-2019-18928)

  - Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16. (CVE-2021-33582)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Rocky Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RLSA-2021:3492 advisory.

  - Cyrus IMAP before 3.4.2 allows remote attackers to cause a denial of service (multiple-minute daemon hang)     via input that is mishandled during hash-table interaction. Because there are many insertions into a     single bucket, strcmp becomes slow. This is fixed in 3.4.2, 3.2.8, and 3.0.16. (CVE-2021-33582)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of cyrus-imapd installed on the remote host is prior to 2.4.22-1.10. It is, therefore, affected by a vulnerability as referenced in the ALAS-2022-1559 advisory.

    A flaw was found in cyrus-imapd. A bad string hashing algorithm used in internal hash tables allows user     inputs to be stored in predictable buckets.  A user may cause a CPU denial of service by maliciously     directing many inputs to a single bucket. The highest threat from this vulnerability is to system     availability. (CVE-2021-33582)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of cyrus-imapd installed on the remote host is prior to 2.4.22-1. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2021-1725 advisory.

    A flaw was found in cyrus-imapd. A bad string hashing algorithm used in internal hash tables allows user     inputs to be stored in predictable buckets.  A user may cause a CPU denial of service by maliciously     directing many inputs to a single bucket. The highest threat from this vulnerability is to system     availability. (CVE-2021-33582)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote CentOS Linux 8 host has packages installed that are affected by a vulnerability as referenced in the CESA-2021:3492 advisory.

  - cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2021:3546 advisory.

    The Cyrus IMAP server provides access to personal mail, system-wide bulletin boards, news-feeds, calendar     and contacts through the IMAP, JMAP, NNTP, CalDAV and CardDAV protocols.

    Security Fix(es):

    * cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 8 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2021-3492 advisory.

    [3.0.7-20.1]
    - Fix for CVE-2021-33582

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2021:3492 advisory.

    The Cyrus IMAP server provides access to personal mail, system-wide bulletin boards, news-feeds, calendar     and contacts through the IMAP, JMAP, NNTP, CalDAV and CardDAV protocols.

    Security Fix(es):

    * cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2021:3493 advisory.

    The Cyrus IMAP server provides access to personal mail, system-wide bulletin boards, news-feeds, calendar     and contacts through the IMAP, JMAP, NNTP, CalDAV and CardDAV protocols.

    Security Fix(es):

    * cyrus-imapd: Denial of service via string hashing algorithm collisions (CVE-2021-33582)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Cyrus IMAP 3.4.2 Release Notes states :

Fixed CVE-2021-33582: Certain user inputs are used as hash table keys during processing. A poorly chosen string hashing algorithm meant that the user could control which bucket their data was stored in, allowing a malicious user to direct many inputs to a single bucket. Each subsequent insertion to the same bucket requires a strcmp of every other entry in it. At tens of thousands of entries, each new insertion could keep the CPU busy in a strcmp loop for minutes. The string hashing algorithm has been replaced with a better one, and now also uses a random seed per hash table, so malicious inputs cannot be precomputed.

ID	Name	Product	Family	Type	Severity
362900	CentOS Linux 7 [TuxCare] Security Update: cyrus-imapd / cyrus-imapd-devel / cyrus-imapd-utils (CENTOS7:CLSA-2026:1790640190)	Nessus	CentOS Local Security Checks	Local	high
359322	Rocky Linux 8 [CIQ] Security Update: cyrus-imapd / cyrus-imapd-debuginfo / cyrus-imapd-debugsource / etc (crlsa-2021_3492)	Nessus	Rocky Linux Local Security Checks	Local	high
293954	MiracleLinux 8 : cyrus-imapd-3.0.7-20.el8.1 (AXSA:2021-2426:03)	Nessus	Miracle Linux Local Security Checks	Local	high
258601	Linux Distros Unpatched Vulnerability : CVE-2021-33582	Nessus	Misc.	Local	high
239739	TencentOS Server 3: cyrus-imapd (TSSA-2022:0245)	Nessus	Tencent Local Security Checks	Local	high
236563	Alibaba Cloud Linux 3 : 0067: cyrus-imapd (ALINUX3-SA-2021:0067)	Nessus	Alibaba Cloud Linux Local Security Checks	Local	critical
214517	Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : Cyrus IMAP Server vulnerabilities (USN-7224-1)	Nessus	Ubuntu Local Security Checks	Local	critical
191315	CentOS 9 : cyrus-imapd-3.4.1-6.el9	Nessus	CentOS Local Security Checks	Local	high
162402	Debian DLA-3052-1 : cyrus-imapd - LTS security update	Nessus	Debian Local Security Checks	Local	critical
157812	Rocky Linux 8 : cyrus-imapd (RLSA-2021:3492)	Nessus	Rocky Linux Local Security Checks	Local	high
156870	Amazon Linux AMI : cyrus-imapd (ALAS-2022-1559)	Nessus	Amazon Linux Local Security Checks	Local	high
155994	Amazon Linux 2 : cyrus-imapd (ALAS-2021-1725)	Nessus	Amazon Linux Local Security Checks	Local	high
153411	CentOS 8 : cyrus-imapd (CESA-2021:3492)	Nessus	CentOS Local Security Checks	Local	high
153404	RHEL 8 : cyrus-imapd (RHSA-2021:3546)	Nessus	Red Hat Local Security Checks	Local	high
153240	Oracle Linux 8 : cyrus-imapd (ELSA-2021-3492)	Nessus	Oracle Linux Local Security Checks	Local	high
153233	RHEL 8 : cyrus-imapd (RHSA-2021:3492)	Nessus	Red Hat Local Security Checks	Local	high
153231	RHEL 8 : cyrus-imapd (RHSA-2021:3493)	Nessus	Red Hat Local Security Checks	Local	high
153073	FreeBSD : cyrus-imapd -- multiple-minute daemon hang via input that is mishandled during hash-table interaction (3d915d96-0b1f-11ec-8d9f-080027415d17)	Nessus	FreeBSD Local Security Checks	Local	high

Detections

Analytics

CVE-2021-33582

high

Tenable Plugins

high

high

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critical

critical

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critical

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high