VulnerabilityPublished 21 Sep 2026Updated 11 Nov 2026

CVE-2026-94184: A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support

Source GCVE Database

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Authoritative record:CVE-2026-94184· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : update Red Hat Enterprise Linux 10 when convenient.

Data as of 11 Nov 2026, 16:47 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Contested

Scorers differ by 2 or more points

CVSS scores by source
CNA (redhat)	CVSS 3.1	5.3
CISA-ADP	CVSS 3.1	8.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-5pfw-5pv2-2pc6

What to do

Patches and advisories

Affected software

Product	Affected	Fixed in
Red Hat Enterprise Linux 10fetchmail	Affected–	Fixed in–
Red Hat Enterprise Linux 10fetchmail	Affected–	Fixed in–
Red Hat Enterprise Linux 8fetchmail	Affected–	Fixed in–
Red Hat Enterprise Linux 9fetchmail	Affected–	Fixed in–
Red Hat Enterprise Linux 9fetchmail	Affected–	Fixed in–
Red Hat Enterprise Linux 6fetchmail	Affected–	Fixed in–

AI-suggested

Red Hat has released an official security update for fetchmail in Red Hat Enterprise Linux 10 and its variants that addresses this vulnerability. Users should apply the update as detailed in the Red Hat advisory RHSA-2026:85959 and the referenced article https://access.redhat.com/articles/11258. No additional mitigation steps are required beyond applying the vendor-provided patch.

Description

A stack-based buffer overflow vulnerability exists in fetchmail when it is built with NTLM support. A malicious or compromised mail server can exploit this by sending a crafted NTLM Type 2 challenge, causing fetchmail to overwrite a fixed stack buffer. This may result in remote code execution, authentication failure, or process termination under memory hardening. Red Hat has released a security update to address this issue in Red Hat Enterprise Linux 10 and its variants.

Impact

The vulnerability allows a remote attacker controlling or compromising a mail server to potentially execute arbitrary code on the client system running fetchmail with NTLM support. Alternatively, it may cause authentication failures or crash the fetchmail process, impacting mail retrieval. The CVSS v3.1 base score is 8.1 (High), reflecting the critical confidentiality, integrity, and availability impacts with network attack vector and no privileges required.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
The product writes past the end of a buffer that was allocated on the stack.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Patches and advisories

Affected software

Description

AI analysisMachine-generated, updated 11 Nov 2026, 16:47 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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