Is CVE-2010-4344 being actively exploited?

Yes. CVE-2010-4344 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on March 25, 2022.

What is the CVSS score for CVE-2010-4344?

CVE-2010-4344 has a CVSS 3.1 base score of 9.8 (CRITICAL).

CVE-2010-4344

CRITICAL · CVSS 9.8CISA KEV: actively exploitedEPSS 71.7%EU EUVD: exploited

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.

Key facts

CVSS score: 9.8 (v3.1)
Severity: CRITICAL
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-787
EPSS score: 71.7% (99th percentile)
In CISA KEV: Yes, added March 25, 2022
In EU EUVD: Yes (EUVD-2010-4313)
Published: December 14, 2010
NVD last modified: June 16, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Exim Heap-Based Buffer Overflow Vulnerability

Added to the KEV catalog on March 25, 2022; federal remediation due April 15, 2022.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2010-4313 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on October 22, 2025.

View on the EU Vulnerability Database

Affected products

canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
debian / debian linux
exim / exim
opensuse / opensuse
opensuse / opensuse
opensuse / opensuse

References

ftp://ftp.exim.org/pub/exim/ChangeLogs/ChangeLog-4.70(Broken Link)
http://atmail.com/blog/2010/atmail-6204-now-available/(Broken Link)
http://bugs.exim.org/show_bug.cgi?id=787(Issue Tracking, Patch)
http://git.exim.org/exim.git/commit/24c929a27415c7cfc7126c47e4cad39acf3efa6b(Mailing List, Patch)
http://lists.exim.org/lurker/message/20101210.164935.385e04d0.en.html(Mailing List, Patch)
http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00003.html(Mailing List, Third Party Advisory)
http://openwall.com/lists/oss-security/2010/12/10/1(Mailing List, Third Party Advisory)
http://secunia.com/advisories/40019(Broken Link, Vendor Advisory)
http://secunia.com/advisories/42576(Broken Link, Vendor Advisory)
http://secunia.com/advisories/42586(Broken Link, Vendor Advisory)
http://secunia.com/advisories/42587(Broken Link, Vendor Advisory)
http://secunia.com/advisories/42589(Broken Link, Vendor Advisory)
http://www.cpanel.net/2010/12/exim-remote-memory-corruption-vulnerability-notification-cve-2010-4344.html(Broken Link)
http://www.debian.org/security/2010/dsa-2131(Mailing List, Third Party Advisory)
http://www.exim.org/lurker/message/20101207.215955.bb32d4f2.en.html(Exploit, Mailing List)
http://www.kb.cert.org/vuls/id/682457(Third Party Advisory, US Government Resource)
http://www.metasploit.com/modules/exploit/unix/smtp/exim4_string_format(Third Party Advisory)
http://www.openwall.com/lists/oss-security/2021/05/04/7(Exploit, Mailing List)
http://www.osvdb.org/69685(Broken Link, Exploit, Patch)
http://www.redhat.com/support/errata/RHSA-2010-0970.html(Broken Link)
http://www.securityfocus.com/archive/1/515172/100/0/threaded(Broken Link, Third Party Advisory, VDB Entry)
http://www.securityfocus.com/bid/45308(Broken Link, Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id?1024858(Broken Link, Third Party Advisory, VDB Entry)
http://www.theregister.co.uk/2010/12/11/exim_code_execution_peril/(Press/Media Coverage)
http://www.ubuntu.com/usn/USN-1032-1(Third Party Advisory)
http://www.vupen.com/english/advisories/2010/3171(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3172(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3181(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3186(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3204(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3246(Broken Link, Vendor Advisory)
http://www.vupen.com/english/advisories/2010/3317(Broken Link)
https://bugzilla.redhat.com/show_bug.cgi?id=661756(Exploit, Issue Tracking)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2010-4344(US Government Resource)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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