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CVE-2010-4344

9.8, critical Known exploited

Exim Heap-Based Buffer Overflow Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
72% higher than 99.4% of scored CVEs
Exploitation
Confirmed in the wild
Published
14 Dec 201015 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 25 Mar 2022. US federal agencies had to remediate by 15 Apr 2022, a deadline that has passed.

Required action. Apply updates per vendor instructions.

Description

Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70 allows remote attackers to execute arbitrary code via an SMTP session that includes two MAIL commands in conjunction with a large message containing crafted headers, leading to improper rejection logging.

Details

Vendor
Exim and 3 more
Product
Exim
Weakness
CWE-787 (opens in a new tab)
Status
Analyzed
Updated
16 Jun 2026
Assigner
secalert@redhat.com

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

References 34

Exploit code 4

Patches and fixes 3

Advisories 20

12 more

Other references 7

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Exim CVEs

Every Exim CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2019-16928 Exim Out-of-bounds Write Vulnerability KEV EPSS 42% 9.8, critical
  • CVE-2019-10149 Exim Mail Transfer Agent (MTA) Improper Input Validation KEV EPSS 100% 9.8, critical
  • CVE-2018-6789 Exim Buffer Overflow Vulnerability KEV EPSS 82% 9.8, critical
  • CVE-2010-4345 Exim Privilege Escalation Vulnerability KEV EPSS 18% 7.8, high
  • CVE-2026-94056 Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled proxy, allows attackers to read certain uninitialized data… EPSS 0.2% 7.5, high

Beyond this page

Is CVE-2010-4344 in your network?

This page tells you how dangerous CVE-2010-4344 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2010-4344 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 16 Oct 2026, not the live upstream state.