Paper/Archive/CVE-2026-113867

CVE-2026-113867

Mozilla Thunderbird — Stanza injection in XMPP chat

CVSS 9.1 (ADP)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 7.5.075 × 201.5 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the 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.

Affected

ProductAffectedFixed inSource

Thunderbirdsee advisory153.5.1CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2080073 refmozilla.org/security/advisories/mfsa2026-114 refmozilla.org/security/advisories/mfsa2026-115