CVE-2026-113867
CVE-2026-113867
- Critical
- CVSS 9.1
- EPSS 0.18%
- No fixed version listed
Summary
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…
From the CVE record.
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CVE record
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 and Thunderbird 153.5.1.
What to do
No fixed version listed
Scores and signals
- Exploitation
- No known exploitation
- Severity
- Critical, CVSS 9.1 (v3.1, scored by CISA-ADP)
- EPSS
- 0.18% chance of exploitation in the next 30 days (EPSS from FIRST, as of Oct 29, 2026)
- CISA's SSVC decision points
- Exploitation: none. Automatable: yes. Technical impact: total. As of Oct 29, 2026.
- Weakness
- CWE-116: Improper Encoding or Escaping of Output
Timeline
- First listed as critical by cve.now. Affected and fixed versions come from the CVE record, once one is published.