CVE-2026-40686

Publication date 29 April 2026

Last updated 4 May 2026

Ubuntu priority

Why this priority?

Cvss 3 Severity Score

Score breakdown

Description

Possible OOB read with large UTF8 trailing characters

Status

Show unmaintained releases

Package	Ubuntu Release	Status
exim4	26.04 LTS resolute	Fixed 4.99.1-1ubuntu1.1
	25.10 questing	Fixed 4.98.2-1ubuntu2.1
	24.04 LTS noble	Fixed 4.97-4ubuntu4.4
	22.04 LTS jammy	Fixed 4.95-4ubuntu2.7
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
exim4	Upstream: ecf4e26

Severity score breakdown

Parameter	Value
Base score	3.7 · Low
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity impact	None
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-8228-1
Exim vulnerabilities
4 May 2026

Other references

Access our resources on patching vulnerabilities