Exim up to 4.99.1 SPA Authentication Driver out-of-bounds write

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in Exim up to 4.99.1. This vulnerability affects unknown code of the component SPA Authentication Driver. The manipulation results in out-of-bounds write. This vulnerability is identified as CVE-2026-40687. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Exim up to 4.99.1. Affected is an unknown functionality of the component SPA Authentication Driver. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability.

The advisory is shared for download at seclists.org. This vulnerability is traded as CVE-2026-40687. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 312296 (Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Exim vulnerabilities (USN-8228-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.99.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (312296). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 312296
Nessus Name: Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Exim vulnerabilities (USN-8228-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Exim 4.99.2

Timelineinfo

04/30/2026 Advisory disclosed
04/30/2026 +0 days VulDB entry created
05/06/2026 +6 days VulDB entry last update

Sourcesinfo

Advisory: seclists.org
Status: Confirmed
Confirmation: 🔒

CVE: CVE-2026-40687 (🔒)
GCVE (CVE): GCVE-0-2026-40687
GCVE (VulDB): GCVE-100-360396

Entryinfo

Created: 04/30/2026 23:15
Updated: 05/06/2026 23:42
Changes: 04/30/2026 23:15 (53), 05/06/2026 23:42 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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