CVE-2006-5553: Cisco Security Agent (CSA) for Linux 4.5 before 4.5.1.657 and 5.0 before 5.0.0.193, as used by Unified CallMan

This month

HIGH 7.8WATCHLISTDOWNGRADEMITIGATEDOWNGRADE

CVE-2006-5553 is a high-severity flaw (CVSS 7.8) affecting security agent, unified callmanager, unified presence server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cisco Security Agent (CSA) for Linux 4.5 before 4.5.1.657 and 5.0 before 5.0.0.193, as used by Unified CallManager (CUCM) and Unified Presence Server (CUPS), allows remote attackers to cause a denial of service (resource consumption) via a port scan with certain options.

Why this priority

High severity
On your watchlist

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

Risk facts

CVSS score	7.8 (High)
EPSS exploit chance	3.2% (top 12%)
CISA exploited list	No
Published	2006-10-26
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: cisco

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

Am I affected?

Timeline

2006-10-26 17:07 UTCPublished CVE record published
2026-06-16 22:31 UTCUpdated Record last modified

cisco security agent DOWNGRADE

Affected: 4.5 · 4.5.1 · 4.5.1.639 · 5.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.5

1. Check installed version

apt-cache policy security-agent || rpm -q security-agent || security-agent --version

2. No fixed release: DOWNGRADE to a release before 4.5 (Debian / Ubuntu)

apt-cache madison security-agent sudo apt install security-agent=<VERSION_BEFORE_4.5> sudo apt-mark hold security-agent

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

dnf --showduplicates list security-agent sudo dnf downgrade security-agent-<VERSION_BEFORE_4.5> sudo dnf versionlock add security-agent

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.

cisco unified callmanager MITIGATE

Affected: 5.0\(1\) · 5.0\(2\) · 5.0\(3\) · 5.0\(3a\) · 5.0\(4\)

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy unified-callmanager || rpm -q unified-callmanager || unified-callmanager --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

cisco unified presence server DOWNGRADE

Affected: 1.0 · 1.0\(2\)

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy unified-presence-server || rpm -q unified-presence-server || unified-presence-server --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison unified-presence-server sudo apt install unified-presence-server=<VERSION_BEFORE_1.0> sudo apt-mark hold unified-presence-server

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

dnf --showduplicates list unified-presence-server sudo dnf downgrade unified-presence-server-<VERSION_BEFORE_1.0> sudo dnf versionlock add unified-presence-server

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.

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-2006-5553?

security agent: downgrade or apply the listed mitigation; unified callmanager: mitigate or apply the listed mitigation; unified presence server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2006-5553 being exploited?

CVE-2006-5553 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-2006-5553 affect?

CVE-2006-5553 affects security agent, unified callmanager, unified presence server. Severity is high (CVSS 7.8). Cisco Security Agent (CSA) for Linux 4.5 before 4.5.1.657 and 5.0 before 5.0.0.193, as used by Unified CallManager (CUCM) and Unified Presence Server (CUPS), allows remote attackers to cause a denial of service (resource consumption) via a

How urgent is CVE-2006-5553?

Priority 54/100. High severity; On your watchlist

Software pages

Cisco vulnerabilities

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References

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