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CVE-2016-9963

17
FAUCET Score

CVE-2016-9963 describes a medium-severity vulnerability in Exim versions prior to 4.87.1, where remote attackers could potentially extract the private DKIM signing key through manipulation of log files and bounce messages. This flaw, categorized as CWE-320 (Key Management Errors), affects various distributions including Canonical and Debian Linux, and their respective Exim packages. The attack requires high complexity but could lead to a high impact on confidentiality, allowing unauthorized access to sensitive cryptographic keys. Despite its potential impact, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 4.87CPE matchmatch criteria
cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
12.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
16.10CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.10:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

5.9MEDIUM

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
3.10%
Probability of exploitation in next 30 days
EPSS Percentile
86.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0310 is in the 80th percentile among its peer group of 19,954 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (6)

boschvendor investigatingvia llm_extracted
citrix_adcvendor investigatingvia llm_extracted
View patch
esetvendor investigatingvia llm_extracted
View patch
giteavendor investigatingvia llm_extracted
View patch
googlevendor investigatingvia llm_extracted
rocketchatvendor investigatingvia llm_extracted

Vendor Advisories (7)

giteallm-gitea-5ea70e0c309e4b8e
Dec 17, 2025
redhatCVE-2016-9963Moderate

exim: Possible information disclosure to remote atacker

Dec 16, 2016
googlellm-google-1d12bd1ba92e22a6

Security Advisory for CVE-2016-9963

esetllm-eset-6bfc7b30f51edf67
citrix_adcllm-citrix_adc-ef116b75dbc6a555
boschllm-bosch-a9903a4b346a6447

Security Advisory for CVE-2016-9963

rocketchatllm-rocketchat-bf05c4ba15e47b77

References

bugs.exim.org / show_bug.cgi
Issue TrackingMitigationVendor Advisory
debian.org / security/2016/dsa-3747
Third Party Advisory
exim.org / static/doc/CVE-2016-9963.txt
MitigationVendor Advisory
securityfocus.com / bid/94947
Third Party AdvisoryVDB Entry
securitytracker.com / id/1037484
Third Party AdvisoryVDB Entry
ubuntu.com / usn/USN-3164-1
Third Party Advisory