CVE-20XX-?

Mozilla Thunderbird CVEs.

Published CVEs affecting Mozilla Thunderbird, ranked by exploit odds.

27 CVEs · updated 2026-11-06 01:30 UTC

  1. CVE-2025-1015

    The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

    Mozilla Thunderbird

    5.4 MEDIUM 1% exploit odds Fix listed
  2. CVE-2026-92240

    A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

    Memory safety Browser & mail Mozilla Thunderbird

    9.1 CRITICAL 0.6% exploit odds Fix listed
  3. CVE-2026-84637

    Malicious calendar invitations could use file URI attachments to launch local or network-hosted executables on Windows, bypassing Thunderbird's normal executable attachment protections. With the new invitation display enabled, the attachment could also appear under a misleading filename. This vulnerability was fixed in Thunderbird 154 and Thunderbird 153.2.

    Code execution Browser & mail Mozilla Thunderbird

    9.8 CRITICAL 0.6% exploit odds Fix listed
  4. CVE-2025-5986

    A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability was fixed in Thunderbird 128.11.1 and Thunderbird 139.0.2.

    Mozilla Thunderbird

    6.5 MEDIUM 0.6% exploit odds Fix listed
  5. CVE-2026-92238

    A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

    Other Browser & mail Mozilla Thunderbird

    9.8 CRITICAL 0.5% exploit odds Fix listed
  6. CVE-2025-3909

    Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

    Mozilla Thunderbird

    8.1 HIGH 0.5% exploit odds Fix listed
  7. CVE-2026-14899

    The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13.

    Mozilla Thunderbird

    7.5 HIGH 0.5% exploit odds Fix listed
  8. CVE-2025-5262

    A double-free could have occurred in `vpx_codec_enc_init_multi` after a failed allocation when initializing the encoder for WebRTC. This could have caused memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 139 and Thunderbird < 128.11.

    Mozilla Thunderbird

    7.5 HIGH 0.5% exploit odds Fix listed
  9. CVE-2026-84642

    The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 155 and Thunderbird 153.2.

    Denial of service Browser & mail Mozilla Thunderbird

    7.5 HIGH 0.4% exploit odds Fix listed
  10. CVE-2026-92239

    A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

    Memory safety Browser & mail Mozilla Thunderbird

    8.1 HIGH 0.4% exploit odds Fix listed
  11. CVE-2025-3875

    Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats [email protected] as the actual address. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

    Mozilla Thunderbird

    7.5 HIGH 0.4% exploit odds Fix listed
  12. CVE-2025-3932

    It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

    Mozilla Thunderbird

    6.5 MEDIUM 0.4% exploit odds Fix listed
  13. CVE-2026-4371

    A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

    Mozilla Thunderbird

    7.4 HIGH 0.4% exploit odds Fix listed
  14. CVE-2025-2830

    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. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

    Mozilla Thunderbird

    6.3 MEDIUM 0.4% exploit odds Fix listed
  15. CVE-2025-26696

    Certain crafted MIME email messages that claimed to contain an encrypted OpenPGP message, which instead contained an OpenPGP signed message, were wrongly shown as being encrypted. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

    Mozilla Thunderbird

    7.0 HIGH 0.4% exploit odds Fix listed
  16. CVE-2026-57962

    A malicious LDAP server, which a Thunderbird user is configured to query for address-book autocomplete, can stash arbitrarily large amounts of attacker-supplied data into the Thunderbird LDAP client until it crashes due to memory exhaustion. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.

    Mozilla Thunderbird

    5.3 MEDIUM 0.3% exploit odds Fix listed
  17. CVE-2026-84639

    Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

    Other Browser & mail Mozilla Thunderbird

    9.1 CRITICAL 0.3% exploit odds Fix listed
  18. CVE-2025-3523

    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. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

    Mozilla Thunderbird

    6.4 MEDIUM 0.3% exploit odds Fix listed
  19. CVE-2026-57963

    An attacker who can send HTML chat messages (via Matrix or XMPP) can inject arbitrary styled content, phishing links, and CSS that manipulates the chat UI. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.

    Mozilla Thunderbird

    6.5 MEDIUM 0.3% exploit odds Fix listed
  20. CVE-2025-0510

    Thunderbird displayed an incorrect sender address if the From field of an email used the invalid group name syntax that is described in CVE-2024-49040. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

    Mozilla Thunderbird

    6.5 MEDIUM 0.3% exploit odds Fix listed
  21. CVE-2026-103500

    An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.

    Memory safety Browser & mail Mozilla Thunderbird

    6.1 MEDIUM 0.3% exploit odds Fix listed
  22. CVE-2025-3522

    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 was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

    Mozilla Thunderbird

    6.3 MEDIUM 0.3% exploit odds Fix listed
  23. CVE-2026-84641

    A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

    Memory safety Browser & mail Mozilla Thunderbird

    7.5 HIGH 0.3% exploit odds Fix listed
  24. CVE-2026-84640

    A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

    Other Browser & mail Mozilla Thunderbird

    7.5 HIGH 0.3% exploit odds Fix listed
  25. CVE-2026-3889

    Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

    Mozilla Thunderbird

    6.5 MEDIUM 0.2% exploit odds Fix listed
  26. CVE-2026-0818

    When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations, then it was possible to extract the secret contents of the email. This vulnerability was fixed in Thunderbird 147.0.1 and Thunderbird 140.7.1.

    Mozilla Thunderbird

    4.3 MEDIUM 0.2% exploit odds Fix listed
  27. CVE-2025-26695

    When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

    Mozilla Thunderbird

    5.3 MEDIUM 0.2% exploit odds Fix listed

All CVEs affecting Mozilla Thunderbird that appear in CVE.org and NVD, sorted by how likely they are to be exploited (EPSS), with fix status and timeline.