CVE-2026-113868
Uninitialized memory disclosure and out-of-bounds read in POP3 and SMTP NTLM authentication
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
5.3
Uninitialized memory disclosure and out-of-bounds read in POP3 and SMTP NTLM authentication
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.
- Record
CVE-2026-113868- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-105295
5.3
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.
- Record
EUVD-2026-105295- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-v77j-vmg8-85hq
5.3
When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the...
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.
- Record
GHSA-v77j-vmg8-85hq- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD
5.3
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.
- Record
CVE-2026-113868- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-113868
5.3
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.
- Record
DEBIAN-CVE-2026-113868- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-113868
5.3
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.
- Record
UBUNTU-CVE-2026-113868- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:12224-1 No score
MozillaThunderbird-153.5.1-1.1 on GA media
These are all security issues fixed in the MozillaThunderbird-153.5.1-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:12224-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
thunderbirdDebian:12 |
before 1:153.5.1esr-1~deb12u1, plus listed versions 1:102.11.0-11:102.12.0-11:102.12.0-1~deb10u11:102.12.0-1~deb11u11:102.12.0-1~deb12u1 Show 45 moreShow less1:102.13.0-11:102.13.0-1~deb10u11:102.13.0-1~deb11u11:102.13.0-1~deb12u11:102.13.1-11:102.13.1-1~deb10u11:102.13.1-1~deb11u11:102.13.1-1~deb12u11:102.14.0-1~deb10u11:102.14.0-1~deb11u11:102.14.0-1~deb12u11:102.15.0-1~deb10u11:102.15.0-1~deb11u11:102.15.0-1~deb12u11:102.15.1-1~deb10u11:102.15.1-1~deb11u11:102.15.1-1~deb12u11:103.0~b5-11:104.0~b2-11:110.0~b4-11:112.0~b1-11:113.0~b3-11:114.0~b2-11:115.0-11:115.0.1-11:115.0.1-21:115.0~b4-11:115.0~b6-11:115.1.0-11:115.1.1-11:115.10.1-11:115.10.1-1~deb10u11:115.10.1-1~deb11u11:115.10.1-1~deb12u11:115.11.0-11:115.11.0-1~deb10u11:115.11.0-1~deb11u11:115.11.0-1~deb12u11:115.12.0-11:115.12.0-1~deb10u11:115.12.0-1~deb11u11:115.12.0-1~deb12u11:115.13.0-11:115.13.0-1~deb11u11:115.13.0-1~deb12u1 |
1:153.5.1esr-1~deb12u1 |
thunderbirdDebian:13 |
before 1:153.5.1esr-1~deb13u1, plus listed versions 1:128.13.0esr-11:128.14.0esr-11:128.14.0esr-1~deb11u11:128.14.0esr-1~deb12u11:128.14.0esr-1~deb13u1 Show 45 moreShow less1:129.0~b6-11:130.0~b3-11:132.0~b6-11:135.0-11:136.0-11:137.0-11:138.0-11:140.0.1esr-11:140.1.0esr-11:140.1.1esr-11:140.10.0esr-11:140.10.0esr-1~deb11u11:140.10.0esr-1~deb12u11:140.10.0esr-1~deb13u11:140.10.1esr-11:140.10.1esr-1~deb11u11:140.10.1esr-1~deb12u11:140.10.1esr-1~deb13u11:140.10.2esr-11:140.10.2esr-1~deb11u11:140.10.2esr-1~deb12u11:140.10.2esr-1~deb13u11:140.11.0esr-11:140.11.0esr-1~deb11u11:140.11.0esr-1~deb12u11:140.11.0esr-1~deb13u11:140.12.0esr-11:140.12.0esr-1~deb11u11:140.12.0esr-1~deb12u11:140.12.0esr-1~deb13u11:140.13.0esr-11:140.13.0esr-21:140.13.0esr-2~deb11u11:140.13.0esr-2~deb12u11:140.13.0esr-2~deb13u11:140.14.0esr-11:140.14.0esr-1~deb11u11:140.14.0esr-1~deb12u11:140.14.0esr-1~deb13u11:140.15.0esr-1~deb12u11:140.15.0esr-1~deb13u11:140.16.0esr-1~deb12u11:140.16.0esr-1~deb13u11:140.17.0esr-1~deb12u11:140.17.0esr-1~deb13u1 |
1:153.5.1esr-1~deb13u1 |
thunderbirdDebian:14 |
All versions, plus listed versions 1:128.13.0esr-11:128.14.0esr-11:128.14.0esr-1~deb11u11:128.14.0esr-1~deb12u11:128.14.0esr-1~deb13u1 Show 45 moreShow less1:129.0~b6-11:130.0~b3-11:132.0~b6-11:135.0-11:136.0-11:137.0-11:138.0-11:140.0.1esr-11:140.1.0esr-11:140.1.1esr-11:140.10.0esr-11:140.10.0esr-1~deb11u11:140.10.0esr-1~deb12u11:140.10.0esr-1~deb13u11:140.10.1esr-11:140.10.1esr-1~deb11u11:140.10.1esr-1~deb12u11:140.10.1esr-1~deb13u11:140.10.2esr-11:140.10.2esr-1~deb11u11:140.10.2esr-1~deb12u11:140.10.2esr-1~deb13u11:140.11.0esr-11:140.11.0esr-1~deb11u11:140.11.0esr-1~deb12u11:140.11.0esr-1~deb13u11:140.12.0esr-11:140.12.0esr-1~deb11u11:140.12.0esr-1~deb12u11:140.12.0esr-1~deb13u11:140.13.0esr-11:140.13.0esr-21:140.13.0esr-2~deb11u11:140.13.0esr-2~deb12u11:140.13.0esr-2~deb13u11:140.14.0esr-11:140.14.0esr-1~deb11u11:140.14.0esr-1~deb12u11:140.14.0esr-1~deb13u11:140.15.0esr-1~deb12u11:140.15.0esr-1~deb13u11:140.16.0esr-1~deb12u11:140.16.0esr-1~deb13u11:140.17.0esr-1~deb12u11:140.17.0esr-1~deb13u1 |
None known |
thunderbirdUbuntu:22.04:LTS |
All versions, plus listed versions 1:91.1.2+build1-0ubuntu11:91.3.0+build2-0ubuntu11:91.3.1+build1-0ubuntu11:91.3.2+build1-0ubuntu11:91.4.0+build1.1-0ubuntu1 Show 34 moreShow less1:91.4.0+build2-0ubuntu11:91.5.0+build1-0ubuntu11:91.5.1+build1-0ubuntu11:91.6.1+build1-0ubuntu11:91.7.0+build1-0ubuntu11:91.7.0+build2-0ubuntu11:91.8.0+build2-0ubuntu11:91.9.1+build1-0ubuntu0.22.04.11:91.11.0+build2-0ubuntu0.22.04.11:102.2.2+build1-0ubuntu0.22.04.11:102.4.2+build2-0ubuntu0.22.04.11:102.7.1+build2-0ubuntu0.22.04.11:102.8.0+build2-0ubuntu0.22.04.11:102.9.0+build1-0ubuntu0.22.04.11:102.10.0+build2-0ubuntu0.22.04.11:102.11.0+build1-0ubuntu0.22.04.11:102.13.0+build1-0ubuntu0.22.04.11:102.15.0+build1-0ubuntu0.22.04.11:102.15.1+build1-0ubuntu0.22.04.11:115.3.1+build1-0ubuntu0.22.04.21:115.4.1+build1-0ubuntu0.22.04.11:115.5.0+build1-0ubuntu0.22.04.11:115.6.0+build2-0ubuntu0.22.04.11:115.8.1+build1-0ubuntu0.22.04.11:115.9.0+build1-0ubuntu0.22.04.11:115.10.1+build1-0ubuntu0.22.04.11:115.11.0+build2-0ubuntu0.22.04.11:115.12.0+build3-0ubuntu0.22.04.11:115.13.0+build5-0ubuntu0.22.04.11:115.15.0+build1-0ubuntu0.22.04.11:115.16.0+build2-0ubuntu0.22.04.11:115.18.0+build1-0ubuntu0.22.04.11:128.12.0+build1-0ubuntu0.22.04.11:140.7.1+build1-0ubuntu0.22.04.1 |
None known |
thunderbirdUbuntu:24.04:LTS |
All versions, plus listed versions 1:115.3.1+build1-0ubuntu11:115.4.1+build1-0ubuntu11:115.4.3+build1-0ubuntu11:115.5.0+build1-0ubuntu11:115.5.1+build1-0ubuntu1 Show 9 moreShow less1:115.5.2+build2-0ubuntu11:115.6.0+build1-0ubuntu11:115.6.0+build2-0ubuntu11:115.6.1+build1-0ubuntu11:115.8.0+build1-0ubuntu11:115.8.1+build1+snap21:115.8.1+build1+snap32:1snap1-0ubuntu12:1snap1-0ubuntu3 |
None known |
thunderbirdUbuntu:26.10 |
All versions, plus listed versions 2:1snap1-0ubuntu5 |
None known |
thunderbirdUbuntu:26.04:LTS |
All versions, plus listed versions 2:1snap1-0ubuntu32:1snap1-0ubuntu42:1snap1-0ubuntu5 |
None known |
MozillaThunderbirdopenSUSE:Tumbleweed From an advisory covering 66 CVEs |
before 153.5.1-1.1 | 153.5.1-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-113868 is a medium vulnerability (CVSS 5.3) in Mozilla Thunderbird, published October 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in thunderbird 1:153.5.1esr-1~deb12u1.
References
bugzilla.mozilla.org/show_bug.cgi?id=2076569
mozilla.org/security/advisories/mfsa2026-114
mozilla.org/security/advisories/mfsa2026-115
nvd.nist.gov/vuln/detail/CVE-2026-113868
github.com/advisories/GHSA-v77j-vmg8-85hq
security-tracker.debian.org/tracker/CVE-2026-113868
Show 69 moreShow less
ubuntu.com/security/CVE-2026-113868
cve.org/CVERecord?id=CVE-2026-113868
mozilla.org/en-US/security/advisories/mfsa2026-115
suse.com/security/cve/CVE-2026-109704
suse.com/security/cve/CVE-2026-109705
suse.com/security/cve/CVE-2026-109706
suse.com/security/cve/CVE-2026-109707
suse.com/security/cve/CVE-2026-109708
suse.com/security/cve/CVE-2026-109709
suse.com/security/cve/CVE-2026-109710
suse.com/security/cve/CVE-2026-109711
suse.com/security/cve/CVE-2026-109712
suse.com/security/cve/CVE-2026-109713
suse.com/security/cve/CVE-2026-109715
suse.com/security/cve/CVE-2026-109716
suse.com/security/cve/CVE-2026-109717
suse.com/security/cve/CVE-2026-109718
suse.com/security/cve/CVE-2026-109719
suse.com/security/cve/CVE-2026-109720
suse.com/security/cve/CVE-2026-109721
suse.com/security/cve/CVE-2026-109722
suse.com/security/cve/CVE-2026-109723
suse.com/security/cve/CVE-2026-109724
suse.com/security/cve/CVE-2026-109725
suse.com/security/cve/CVE-2026-109726
suse.com/security/cve/CVE-2026-109727
suse.com/security/cve/CVE-2026-109728
suse.com/security/cve/CVE-2026-109729
suse.com/security/cve/CVE-2026-109730
suse.com/security/cve/CVE-2026-109731
suse.com/security/cve/CVE-2026-109732
suse.com/security/cve/CVE-2026-109733
suse.com/security/cve/CVE-2026-109734
suse.com/security/cve/CVE-2026-109736
suse.com/security/cve/CVE-2026-109737
suse.com/security/cve/CVE-2026-109738
suse.com/security/cve/CVE-2026-109740
suse.com/security/cve/CVE-2026-109741
suse.com/security/cve/CVE-2026-109742
suse.com/security/cve/CVE-2026-109743
suse.com/security/cve/CVE-2026-109744
suse.com/security/cve/CVE-2026-109745
suse.com/security/cve/CVE-2026-109751
suse.com/security/cve/CVE-2026-109752
suse.com/security/cve/CVE-2026-109753
suse.com/security/cve/CVE-2026-109754
suse.com/security/cve/CVE-2026-109756
suse.com/security/cve/CVE-2026-109757
suse.com/security/cve/CVE-2026-109759
suse.com/security/cve/CVE-2026-109760
suse.com/security/cve/CVE-2026-109762
suse.com/security/cve/CVE-2026-109763
suse.com/security/cve/CVE-2026-109764
suse.com/security/cve/CVE-2026-109765
suse.com/security/cve/CVE-2026-109766
suse.com/security/cve/CVE-2026-109767
suse.com/security/cve/CVE-2026-109770
suse.com/security/cve/CVE-2026-109775
suse.com/security/cve/CVE-2026-109776
suse.com/security/cve/CVE-2026-109777
suse.com/security/cve/CVE-2026-109778
suse.com/security/cve/CVE-2026-109781
suse.com/security/cve/CVE-2026-109782
suse.com/security/cve/CVE-2026-109783
suse.com/security/cve/CVE-2026-110249
suse.com/security/cve/CVE-2026-113470
suse.com/security/cve/CVE-2026-113866
suse.com/security/cve/CVE-2026-113867
suse.com/security/cve/CVE-2026-113868
Left out here: 305 versions. The JSON record has them.