Mozilla Thunderbird up to 158.0.0 Chat injection

Summaryinfo

A vulnerability was found in Mozilla Thunderbird up to 158.0.0. It has been rated as problematic. This vulnerability affects unknown code of the component Chat. The manipulation leads to injection. This vulnerability is referenced as CVE-2026-113867. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Mozilla Thunderbird up to 158.0.0. This issue affects an unknown function of the component Chat. The manipulation with an unknown input leads to a injection vulnerability. Using CWE to declare the problem leads to CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. Impacted is integrity. The summary by CVE is:

Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would then process as if sent by the user. This could be used to send messages or change contact and subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's chat feature with XMPP accounts. This vulnerability was fixed in Thunderbird 158.0.1.

It is possible to read the advisory at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2026-113867 since 10/20/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/20/2026). The attack technique deployed by this issue is T1055 according to MITRE ATT&CK.

Upgrading to version 158.0.1 eliminates this vulnerability.

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Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 158.0

License

• open-source

Website

• Vendor: https://www.mozilla.org/

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