Threats / Exim / CVE-2010-4344
CVE-2010-4344
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Exim vulnerability
Heap-based buffer overflow in Exim's string_vformat function allows remote attackers to execute arbitrary code via SMTP sessions.
Verdict
Today item — known-exploited.
A remote code execution vulnerability in Exim before version 4.70 enables unauthenticated attackers to trigger a heap buffer overflow through SMTP protocol interaction, leading to arbitrary code execution on affected mail servers.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25).
Probability (EPSS)
EPSS 0.71794 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Exim, Exim. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-119 Memory Buffer Bounds Error — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious SMTP message designed to overflow the heap buffer in the string_vformat function.
Business
Mail infrastructure becomes a direct attack surface for remote code execution without authentication.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send the payload through an SMTP session to trigger the overflow and gain code execution on the server.
Business
Attackers obtain shell access to mail servers, compromising email systems and potentially the broader network.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistence and move laterally to other systems or exfiltrate sensitive email data.
Business
Email confidentiality and integrity are compromised; organizational data and communications are exposed to theft or manipulation.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05