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NVD Vulnerability Details :
CVE-2026-40686
Analyzed
More InfoOfficial Page
Source-cve@mitre.org
View Known Exploited Vulnerability (KEV) details
Published At-30 Apr, 2026 | 22:16
Updated At-01 May, 2026 | 17:44

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.13.7LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Primary3.15.3MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Type: Secondary
Version: 3.1
Base score: 3.7
Base severity: LOW
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Type: Primary
Version: 3.1
Base score: 5.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CPE Matches
Exim
exim
>>exim>>Versions before 4.99.2(exclusive)
cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-125Secondarycve@mitre.org
CWE ID: CWE-125
Type: Secondary
Source: cve@mitre.org
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efccve@mitre.org
Patch
https://exim.org/static/doc/security/CVE-2026-40686.txtcve@mitre.org
Broken Link
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessmentcve@mitre.org
Vendor Advisory
https://www.openwall.com/lists/oss-security/2026/04/30/21cve@mitre.org
Mailing List
Third Party Advisory
Hyperlink: https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc
Source: cve@mitre.org
Resource:
Patch
Hyperlink: https://exim.org/static/doc/security/CVE-2026-40686.txt
Source: cve@mitre.org
Resource:
Broken Link
Hyperlink: https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment
Source: cve@mitre.org
Resource:
Vendor Advisory
Hyperlink: https://www.openwall.com/lists/oss-security/2026/04/30/21
Source: cve@mitre.org
Resource:
Mailing List
Third Party Advisory
Change History
0Changes found
Details not found