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NVD Vulnerability Details :
CVE-2026-40685
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 | 17:51

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.

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
Secondary3.16.5MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Primary3.19.8CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Type: Secondary
Version: 3.1
Base score: 6.5
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Type: Primary
Version: 3.1
Base score: 9.8
Base severity: CRITICAL
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CPE Matches
Exim
exim
>>exim>>Versions before 4.99.2(exclusive)
cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-684Secondarycve@mitre.org
CWE-787Primarynvd@nist.gov
CWE ID: CWE-684
Type: Secondary
Source: cve@mitre.org
CWE ID: CWE-787
Type: Primary
Source: nvd@nist.gov
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
https://code.exim.org/exim/exim/commit/9fdc057e71b87c87a0d3d2288b2810a0efaaba57cve@mitre.org
Patch
https://exim.org/static/doc/security/CVE-2026-40685.txtcve@mitre.org
Broken Link
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40685.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/9fdc057e71b87c87a0d3d2288b2810a0efaaba57
Source: cve@mitre.org
Resource:
Patch
Hyperlink: https://exim.org/static/doc/security/CVE-2026-40685.txt
Source: cve@mitre.org
Resource:
Broken Link
Hyperlink: https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40685.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