CVE-2007-0756: Chicken of the VNC (cotv) 2.0 allows remote attackers to cause a denial of service (application crash) via a l

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HIGH 7.8DOWNGRADE

CVE-2007-0756 is a high-severity flaw (CVSS 7.8) affecting chicken of the vnc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Chicken of the VNC (cotv) 2.0 allows remote attackers to cause a denial of service (application crash) via a large computer-name size value in a ServerInit packet, which triggers a failed malloc and a resulting NULL dereference.

Why this priority

High severity
EPSS top 9%: very likely to be exploited
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
EPSS exploit chance	4.4% (top 9%)
CISA exploited list	No
Published	2007-02-06
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: chicken of the vnc

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2007-02-06 02:28 UTCPublished CVE record published
2026-06-16 22:36 UTCUpdated Record last modified

chicken of the vnc chicken of the vnc DOWNGRADE

Affected: 2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0

1. Check installed version

apt-cache policy chicken-of-the-vnc || rpm -q chicken-of-the-vnc || chicken-of-the-vnc --version

2. No fixed release: DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison chicken-of-the-vnc sudo apt install chicken-of-the-vnc=<VERSION_BEFORE_2.0> sudo apt-mark hold chicken-of-the-vnc

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list chicken-of-the-vnc sudo dnf downgrade chicken-of-the-vnc-<VERSION_BEFORE_2.0> sudo dnf versionlock add chicken-of-the-vnc

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Chicken of the VNC 2.0 - 'NULL-pointer' Remote Denial of Service

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-2007-0756?

chicken of the vnc: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2007-0756 being exploited?

CVE-2007-0756 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-2007-0756 affect?

CVE-2007-0756 affects chicken of the vnc. Severity is high (CVSS 7.8). Chicken of the VNC (cotv) 2.0 allows remote attackers to cause a denial of service (application crash) via a large computer-name size value in a ServerInit packet, which triggers a failed malloc and a resulting NULL dereference.

How urgent is CVE-2007-0756?

Priority 55/100. High severity; EPSS top 9%: very likely to be exploited; Public exploit reference

References

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