CVE-2018-0683: Buffer overflow in Denbun by NEOJAPAN Inc

Q: How do I fix CVE-2018-0683?

debun imap: upgrade to newer than 3.3i_r4.0; debun pop: upgrade to newer than 3.3p_r4.0. Exact commands for each OS are on this page.

Q: Is CVE-2018-0683 being exploited?

CVE-2018-0683 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2018-0683 affect?

CVE-2018-0683 affects debun imap, debun pop. Severity is critical (CVSS 9.8). Buffer overflow in Denbun by NEOJAPAN Inc. (Denbun POP version V3.3P R4.0 and earlier, Denbun IMAP version V3.3I R4.0 and earlier) allows remote attackers to execute arbitrary code or cause a denial-of-service (DoS) condition via Cookie dat

Q: How urgent is CVE-2018-0683?

Priority 62/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADEUPGRADE

CVE-2018-0683 is a critical-severity flaw (CVSS 9.8) affecting debun imap, debun pop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in Denbun by NEOJAPAN Inc. (Denbun POP version V3.3P R4.0 and earlier, Denbun IMAP version V3.3I R4.0 and earlier) allows remote attackers to execute arbitrary code or cause a denial-of-service (DoS) condition via Cookie data.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.6% (top 11%)
CISA exploited list	No
Weakness	CWE-119
Published	2018-11-15
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: neo

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-11-15 15:29 UTCPublished CVE record published
2026-06-17 01:31 UTCUpdated Record last modified

neo debun imap UPGRADE

Affected: <= 3.3i_r4.0

Fixed in: newer than 3.3i_r4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy debun-imap || rpm -q debun-imap || debun-imap --version

2. UPGRADE to newer than 3.3i_r4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade debun-imap

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade debun-imap

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

neo debun pop UPGRADE

Affected: <= 3.3p_r4.0

Fixed in: newer than 3.3p_r4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy debun-pop || rpm -q debun-pop || debun-pop --version

2. UPGRADE to newer than 3.3p_r4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade debun-pop

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade debun-pop

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-0683?

debun imap: upgrade to newer than 3.3i_r4.0; debun pop: upgrade to newer than 3.3p_r4.0. Exact commands for each OS are on this page.

Is CVE-2018-0683 being exploited?

CVE-2018-0683 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-0683 affect?

CVE-2018-0683 affects debun imap, debun pop. Severity is critical (CVSS 9.8). Buffer overflow in Denbun by NEOJAPAN Inc. (Denbun POP version V3.3P R4.0 and earlier, Denbun IMAP version V3.3I R4.0 and earlier) allows remote attackers to execute arbitrary code or cause a denial-of-service (DoS) condition via Cookie dat

How urgent is CVE-2018-0683?

Priority 62/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2018-0687 MEDIUM 6.1 UPGRADE UPGRADE Cross-site scripting vulnerability in Denbun by NEOJAPAN Inc
CVE-2018-0686 HIGH 8.8 UPGRADE UPGRADE Denbun by NEOJAPAN Inc
CVE-2018-0684 CRITICAL 9.8 UPGRADE UPGRADE Buffer overflow in Denbun by NEOJAPAN Inc
CVE-2018-0682 CRITICAL 9.8 UPGRADE UPGRADE Denbun by NEOJAPAN Inc
CVE-2018-0681 CRITICAL 9.8 UPGRADE UPGRADE Denbun by NEOJAPAN Inc

References

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