Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.

The remote AlmaLinux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the ALSA-2025:4229 advisory.

    * thunderbird: User Interface (UI) Misrepresentation of attachment URL (CVE-2025-3523)
      * thunderbird: Information Disclosure of /tmp directory listing (CVE-2025-2830)
      * thunderbird: Leak of hashed Window credentials via crafted attachment URL (CVE-2025-3522)

Tenable has extracted the preceding description block directly from the AlmaLinux 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 Oracle Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2025-4229 advisory.

    [128.9.2-1.0.1]
    - Fix prefs for new nss [Orabug: 37079813]
    - Add Oracle prefs

    [128.9.2]
    - Add OpenELA debranding

    [128.9.2-1]
    - Update to 128.9.2

Tenable has extracted the preceding description block directly from the Oracle 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 Redhat Enterprise Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2025:4229 advisory.

    Mozilla Thunderbird is a standalone mail and newsgroup client.

    Security Fix(es):

    * thunderbird: User Interface (UI) Misrepresentation of attachment URL (CVE-2025-3523)

    * thunderbird: Information Disclosure of /tmp directory listing (CVE-2025-2830)

    * thunderbird: Leak of hashed Window credentials via crafted attachment URL (CVE-2025-3522)

    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 these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 40 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2025-fd8eb9ca57 advisory.

    Update to 128.9.2

    * https://www.thunderbird.net/en-US/thunderbird/128.9.1esr/releasenotes/
    * https://www.thunderbird.net/en-US/thunderbird/128.9.2esr/releasenotes/
    * https://www.mozilla.org/en-US/security/advisories/mfsa2025-27/

Tenable has extracted the preceding description block directly from the Fedora 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 SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2025:1366-1 advisory.

    - Mozilla Thunderbird 128.9.2 (bsc#1241277)
    - CVE-2025-3522: Leak of hashed Window credentials via crafted attachment URL
    - CVE-2025-2830: Information Disclosure of /tmp directory listing
    - CVE-2025-3523: User Interface (UI) Misrepresentation of attachment URL

Tenable has extracted the preceding description block directly from the SUSE 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 Fedora 41 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2025-9e6d18cb4f advisory.

    Update to 128.9.2

    * https://www.thunderbird.net/en-US/thunderbird/128.9.1esr/releasenotes/
    * https://www.thunderbird.net/en-US/thunderbird/128.9.2esr/releasenotes/
    * https://www.mozilla.org/en-US/security/advisories/mfsa2025-27/

Tenable has extracted the preceding description block directly from the Fedora 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 version of Thunderbird installed on the remote Windows host is prior to 137.0.2. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2025-26 advisory.

  - Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be     hosted externally. When an email is opened, Thunderbird accesses the specified URL to  determine file     size, and navigates to it when the user clicks the attachment. Because the URL is not validated or     sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially     leading to hashed Windows credential leakage and opening the door to more serious security issues.
    (CVE-2025-3522)

  - By crafting a malformed file name for an attachment in a multipart message, an attacker can trick     Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new     message. This vulnerability could allow attackers to disclose sensitive information from the victim's     system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well.
    (CVE-2025-2830)

  - When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL     header, only the last link is shown when hovering over any attachment. Although the correct link is used     on click, the misleading hover text could trick users into downloading content from untrusted sources.
    (CVE-2025-3523)

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

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 137.0.2. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2025-26 advisory.

  - Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be     hosted externally. When an email is opened, Thunderbird accesses the specified URL to  determine file     size, and navigates to it when the user clicks the attachment. Because the URL is not validated or     sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially     leading to hashed Windows credential leakage and opening the door to more serious security issues.
    (CVE-2025-3522)

  - By crafting a malformed file name for an attachment in a multipart message, an attacker can trick     Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new     message. This vulnerability could allow attackers to disclose sensitive information from the victim's     system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well.
    (CVE-2025-2830)

  - When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL     header, only the last link is shown when hovering over any attachment. Although the correct link is used     on click, the misleading hover text could trick users into downloading content from untrusted sources.
    (CVE-2025-3523)

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

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 128.9.2. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2025-27 advisory.

  - When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL     header, only the last link is shown when hovering over any attachment. Although the correct link is used     on click, the misleading hover text could trick users into downloading content from untrusted sources.
    (CVE-2025-3523)

  - Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be     hosted externally. When an email is opened, Thunderbird accesses the specified URL to  determine file     size, and navigates to it when the user clicks the attachment. Because the URL is not validated or     sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially     leading to hashed Windows credential leakage and opening the door to more serious security issues.
    (CVE-2025-3522)

  - By crafting a malformed file name for an attachment in a multipart message, an attacker can trick     Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new     message. This vulnerability could allow attackers to disclose sensitive information from the victim's     system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well.
    (CVE-2025-2830)

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

The version of Thunderbird installed on the remote Windows host is prior to 128.9.2. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2025-27 advisory.

  - When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL     header, only the last link is shown when hovering over any attachment. Although the correct link is used     on click, the misleading hover text could trick users into downloading content from untrusted sources.
    (CVE-2025-3523)

  - Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be     hosted externally. When an email is opened, Thunderbird accesses the specified URL to  determine file     size, and navigates to it when the user clicks the attachment. Because the URL is not validated or     sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially     leading to hashed Windows credential leakage and opening the door to more serious security issues.
    (CVE-2025-3522)

  - By crafting a malformed file name for an attachment in a multipart message, an attacker can trick     Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new     message. This vulnerability could allow attackers to disclose sensitive information from the victim's     system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well.
    (CVE-2025-2830)

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

The version of mozilla-thunderbird installed on the remote host is prior to 128.9.2esr. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2025-105-01 advisory.

    New mozilla-thunderbird packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the mozilla-thunderbird security advisory.

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

ID	Name	Product	Family	Severity
234913	AlmaLinux 9 : thunderbird (ALSA-2025:4229)	Nessus	Alma Linux Local Security Checks	medium
234903	Oracle Linux 9 : thunderbird (ELSA-2025-4229)	Nessus	Oracle Linux Local Security Checks	medium
234887	RHEL 9 : thunderbird (RHSA-2025:4229)	Nessus	Red Hat Local Security Checks	medium
234881	Fedora 40 : thunderbird (2025-fd8eb9ca57)	Nessus	Fedora Local Security Checks	medium
234842	SUSE SLED15 / SLES15 / openSUSE 15 Security Update : MozillaThunderbird (SUSE-SU-2025:1366-1)	Nessus	SuSE Local Security Checks	medium
234695	Fedora 41 : thunderbird (2025-9e6d18cb4f)	Nessus	Fedora Local Security Checks	medium
234492	Mozilla Thunderbird < 137.0.2	Nessus	Windows	medium
234491	Mozilla Thunderbird < 137.0.2	Nessus	MacOS X Local Security Checks	medium
234457	Mozilla Thunderbird < 128.9.2	Nessus	MacOS X Local Security Checks	medium
234456	Mozilla Thunderbird < 128.9.2	Nessus	Windows	medium
234455	Slackware Linux 15.0 / current mozilla-thunderbird Multiple Vulnerabilities (SSA:2025-105-01)	Nessus	Slackware Local Security Checks	medium

Detections

Analytics

CVE-2025-3522

medium

Tenable Plugins

medium

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medium