A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.01195.

Exploitation none

Automatable no

Technical Impact total

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Red Hat Red Hat Enterprise Linux 10 affected
Version Status Constraints
0:6.4.38-3.el10_2.1 unaffected < *
Red Hat Red Hat Enterprise Linux 8 affected
Version Status Constraints
0:6.4.24-1.el8_10.1 unaffected < *
Red Hat Red Hat Enterprise Linux 9 affected
Version Status Constraints
0:6.4.24-1.el9_8.1 unaffected < *
Red Hat Red Hat Enterprise Linux 6 affected —
Red Hat Red Hat Enterprise Linux 7 affected —

No data.

No data.

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Vendors Products
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Project Subscriptions

Vendors Products
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Enterprise Linux Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

Rebuild fetchmail without --enable-NTLM (omit NTLM at configure time). Confirm with `fetchmail -V` that the build does not list +NTLM.

References
Link Providers
http://www.openwall.com/lists/oss-security/2026/09/23/1 cve-icon
https://access.redhat.com/errata/RHSA-2026:85959 cve-icon cve-icon
https://access.redhat.com/errata/RHSA-2026:86981 cve-icon cve-icon
https://access.redhat.com/errata/RHSA-2026:86982 cve-icon cve-icon
https://access.redhat.com/security/cve/CVE-2026-94184 cve-icon cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2531984 cve-icon cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2537395 cve-icon cve-icon
https://gitlab.com/fetchmail/fetchmail/-/commit/cb5be5c38471eec19e519ace0bc569176317ea92 cve-icon cve-icon
https://www.fetchmail.info/fetchmail-SA-2026-01.txt cve-icon cve-icon
https://www.openwall.com/lists/oss-security/2026/06/27/8 cve-icon cve-icon
History

Wed, 21 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
References

Wed, 21 Oct 2026 14:00:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
References

Tue, 20 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References

Thu, 01 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

 cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Tue, 29 Sep 2026 19:45:00 +0000

Type Values Removed Values Added
Description A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening. Affects v5.0.8 through v6.6.6. A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening.

Wed, 23 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Wed, 23 Sep 2026 03:30:00 +0000

Type Values Removed Values Added
References

Tue, 22 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Mon, 21 Sep 2026 16:45:00 +0000

Type Values Removed Values Added
Description A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening. A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening. Affects v5.0.8 through v6.6.6.

Mon, 21 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Mon, 21 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Description A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening.
Title Fetchmail: fetchmail: stack-based buffer overflow in ntlm authentication (fetchmail-sa-2026-01)
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-121
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-10-21T14:01:53.606Z

Reserved: 2026-09-21T01:48:54.590Z

Link: CVE-2026-94184

cve-icon Vulnrichment

Updated: 2026-09-23T03:09:26.497Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-21T15:17:38.547

Modified: 2026-10-21T15:17:19.630

Link: CVE-2026-94184

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T22:45:13Z

Weaknesses