CVE-2026-113866CWE-523

CVE-2026-113866

Medium · published October 21, 2026

CVSS v3.1
5.9
EPSS
0%
Percentile
29.1
In the wild
Unconfirmed
What it is

When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.

The record
Technical detail
CVSS v3.1
5.9 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00365 · 29.1th percentile
Weakness
CWE-523 · Unprotected Transport of Credentials
Published
2026-10-21T00:17Z
References (3)
https://bugzilla.mozilla.org/show_bug.cgi?id=2080121 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-114/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-115/ · [email protected]
EPSS history
Timeline
  • 22 OCT 03:29Z
    EPSS moved — → 0%
    epss
  • 20 OCT 19:14Z
    Account password sent unencrypted during Exchange account setup
    cvelistv5
  • 20 OCT 19:14Z
    Account password sent unencrypted during Exchange account setup
    cvelistv5