CVE-2004-1940: sipclient.cpp in KPhone 4.0.1 and earlier allows remote attackers to cause a denial of service (crash) via a S

Q: How do I fix CVE-2004-1940?

kphone: upgrade to newer than 4.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2004-1940 being exploited?

CVE-2004-1940 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-2004-1940 affect?

CVE-2004-1940 affects kphone. Severity is medium (CVSS 5.0). sipclient.cpp in KPhone 4.0.1 and earlier allows remote attackers to cause a denial of service (crash) via a STUN response packet with a large attrLen value that causes an out-of-bounds read.

Q: How urgent is CVE-2004-1940?

Priority 45/100. EPSS top 9%: very likely to be exploited; Public exploit reference

This month

MEDIUM 5.0UPGRADE

CVE-2004-1940 is a medium-severity flaw (CVSS 5.0) affecting kphone. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

sipclient.cpp in KPhone 4.0.1 and earlier allows remote attackers to cause a denial of service (crash) via a STUN response packet with a large attrLen value that causes an out-of-bounds read.

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	4.1% (top 9%)
CISA exploited list	No
Weakness	CWE-125
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: wirlab

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:08 UTCUpdated Record last modified

wirlab kphone UPGRADE

Affected: <= 4.0.1

Fixed in: newer than 4.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy kphone || rpm -q kphone || kphone --version

2. UPGRADE to newer than 4.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade kphone

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade kphone

Note

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

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: KPhone 2.x/3.x/4.0.1 - Malformed STUN Packet 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-2004-1940?

kphone: upgrade to newer than 4.0.1. Exact commands for each OS are on this page.

Is CVE-2004-1940 being exploited?

CVE-2004-1940 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-2004-1940 affect?

CVE-2004-1940 affects kphone. Severity is medium (CVSS 5.0). sipclient.cpp in KPhone 4.0.1 and earlier allows remote attackers to cause a denial of service (crash) via a STUN response packet with a large attrLen value that causes an out-of-bounds read.

How urgent is CVE-2004-1940?

Priority 45/100. EPSS top 9%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2006-2442 MEDIUM 4.6 DOWNGRADE kphone 4.2 creates .qt/kphonerc with world-readable permissions, which allows local users to read usernames an

References

← Back to latest CVEs