Stanza injection in Thunderbird XMPP chat
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
Mozilla Thunderbird does not escape attribute values when it serializes outgoing XMPP stanzas for its chat feature. Because values from incoming requests are echoed back in automatic replies, a remote XMPP user can send a crafted request that makes Thunderbird inject arbitrary stanzas into the user's connection, a flaw caused by improper encoding of output (CWE-116). The server processes the injected stanzas as if the user sent them, so an attacker without any user interaction can send messages or change contact and subscription settings on the user's behalf.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Mozilla Thunderbird is fixed in 153.5.1 and 158.0.1, so update to one of these versions. The sources list no fixed version for Red Hat Enterprise Linux 8, 9 and 10.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
- Fix · CNA Thunderbird (Mozilla) Fixed in 153.5.1, 158.0.1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-20 Threatist record created from CVE-2026-113867
- 2026-10-21 Alias added: GHSA-7qpm-g2hw-rqrc
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score added · Red Hat
- 2026-10-29 CVSS score added · CISA ADP
- 2026-10-29 Weakness changed · CISA ADP
- 2026-10-29 CISA SSVC decision points changed
- 2026-10-29 Priority changed: LOW → MEDIUM
References
More Mozilla vulnerabilities
- TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
- TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
- TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
- TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
- TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
- TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2026-113867 · CVE Program
- CVE-2026-113867 · NVD
- FIRST EPSS
- GHSA-7qpm-g2hw-rqrc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-113867 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences