CVE•Published 2026-04-30•Modified 2026-05-01•0 articles on news•5 live references•NVD data

CVE-2026-40684Exim · Exim

Vulnerability data via NVD (ingested)

CVSS v3.1

5.9

MEDIUM

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

EPSS percentile

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Weaknesses (CWE)

CWE-684Incorrect Provision of Specified Functionality

Description

In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.

Timeline

Published 2026-04-30

Modified 2026-05-01

External references

NVD MITRE Exploit-DB Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag524,838 hosts

vuln:CVE-2026-40684

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Exim Exim"

All exposed Exim Exim instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Exim"

HTTP body or banner mentions "Exim" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-40684