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Vulnerabilities

Vulnerability · CVE-2010-4344

Exim Heap-Based Buffer Overflow Vulnerability

Published Dec 10, 2010 · catalog updated Jun 16, 2026 · Exim Exim

Patch now

CVE-2010-4344 is in the CISA known-exploited catalog, due Apr 15, 2022. Confirm Exim Exim against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
71.71%
Remediation
Remediation guidance
Affected products
cpe canonical/ubuntu linux · cpe debian/debian linux · cpe exim/exim · cpe opensuse/opensuse · vendor Exim Exim · vendor n/a n/a

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe canonical/ubuntu linux6.06
  • cpe canonical/ubuntu linux8.04
  • cpe canonical/ubuntu linux9.10
  • cpe debian/debian linux5.0
  • cpe exim/eximversion unspecified
  • cpe opensuse/opensuse11.1
  • cpe opensuse/opensuse11.2
  • cpe opensuse/opensuse11.3
  • vendor Exim Eximversion unspecified
  • vendor n/a n/aversion unspecified

How to fix CVE-2010-4344

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2010-4344 is in the CISA known-exploited catalog, due Apr 15, 2022. Confirm Exim Exim against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with canonical/ubuntu linux 6.06; canonical/ubuntu linux 8.04; canonical/ubuntu linux 9.10; debian/debian linux 5.0. Apply updates per vendor instructions.

What should an analyst verify?

CWE-119: Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 71.71%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 14, 2010 · Catalog

    Detected

    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.

  2. Mar 25, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Apr 15, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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.

Sources

  • CISA KEVConfirmed exploitationCVE-2010-4344

    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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2010-4344

    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 reje

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2010-4344

    30-day exploitation probability 71.7%

    first.org
  • Exploit DatabasePublic exploit reference15725

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Exploit DatabasePublic exploit reference16925

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Metasploit ModulesPublic exploit moduleexploit_unix/smtp/exim4_string_format

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2010-4344

    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 reje

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2010-4344

    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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.