CVE-2016-9963

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via...

5.9 MediumFix available

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

3.10%Up 1.8 points since Feb 4, 2022

What each source reports

NVD Score used 5.9

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: CVE-2016-9963
CVSS 3.0: 5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0: 2.6 LowAV:N/AC:H/Au:N/C:P/I:N/A:N
Weakness: CWE-320
Updated: 2026-11-02

CVE List No score

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: CVE-2016-9963
Updated: 2026-11-02

EUVDEUVD-2016-10748 No score

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: EUVD-2016-10748
Updated: 2026-11-03

GitHub AdvisoriesGHSA-qf64-f8r5-29m4 5.9

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via...

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: GHSA-qf64-f8r5-29m4
CVSS 3.0: 5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSV 5.9

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: CVE-2016-9963
CVSS 3.0: 5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVDEBIAN-CVE-2016-9963 5.9

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: DEBIAN-CVE-2016-9963
CVSS 3.0: 5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2016-9963 5.9

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Record: UBUNTU-CVE-2016-9963
CVSS 3.0: 5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVopenSUSE-SU-2024:10746-1 No score

exim-4.94.2-4.2 on GA media

These are all security issues fixed in the exim-4.94.2-4.2 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2024:10746-1
Updated: 2026-11-02

OSVUSN-3164-1 No score

exim4 vulnerability

Bjoern Jacke discovered that Exim incorrectly handled DKIM keys. In certain configurations, private DKIM signing keys could be leaked to the log files.

Record: USN-3164-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`exim4` Debian:12	before 4.88~RC6-2	4.88~RC6-2
`exim4` Debian:13	before 4.88~RC6-2	4.88~RC6-2
`exim4` Debian:14	before 4.88~RC6-2	4.88~RC6-2
`exim4` Debian:7	before 4.80-7+deb7u4, plus listed versions 4.80-74.80-7+deb7u14.80-7+deb7u24.80-7+deb7u3	4.80-7+deb7u4
`exim4` Debian:8	before 4.84.2-2+deb8u2, plus listed versions 4.84-84.84-8+deb8u14.84-8+deb8u24.84.2-14.84.2-1+deb8u14.84.2-24.84.2-2+deb8u1	4.84.2-2+deb8u2
`exim4` Ubuntu:14.04:LTS	before 4.82-3ubuntu2.2, plus listed versions 4.80-7ubuntu34.80-7ubuntu44.80-9ubuntu14.80-9ubuntu24.82-3ubuntu14.82-3ubuntu24.82-3ubuntu2.1	4.82-3ubuntu2.2
`exim4` Ubuntu:16.04:LTS	before 4.86.2-2ubuntu2.1, plus listed versions 4.86-3ubuntu14.86-7ubuntu14.86-7ubuntu24.86-7ubuntu34.86.2-2ubuntu14.86.2-2ubuntu2	4.86.2-2ubuntu2.1
`exim` openSUSE:Tumbleweed From an advisory covering 31 CVEs	before 4.94.2-4.2	4.94.2-4.2

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2016-9963 is a medium vulnerability (CVSS 5.9) in Exim, published December 16, 2016. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.10%, the 87th percentile. Fixed in exim4 4.88~RC6-2.

References

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