CVE-2026-113868Uninitialized memory disclosure and out-of-bounds read in POP3 and SMTP NTLM authentication
Updated under an hour ago ()
Does this affect you?
It affects Mozilla Thunderbird. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
- CVSS
- 5.3 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-125
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Received
- Record last updated
- Oct 20, 2026
- First seen by InfoSec Signals
- Oct 20, 2026
Affected products
Mozilla Thunderbird mozilla:thunderbird (from the name) | 153.5.1 builds before 153.* not affected; from 158.0.1 not affected | CNA record |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2076569
- https://www.mozilla.org/security/advisories/mfsa2026-114/
- https://www.mozilla.org/security/advisories/mfsa2026-115/
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.