# What is CVE-2006-4855?

> CVE-2006-4855 is a medium-severity flaw (CVSS 4.9) in Client Security from Symantec, published on 19 September 2006. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 1.3%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2006-4855

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **Precursor Intelligence risk score:** 37 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 4.9 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 1.3% (latest exploit-likelihood forecast)
- **Published:** 19 September 2006
- **Record last updated:** 16 June 2026
- **Main product:** Client Security from Symantec
- **Affected products:** 7

## What is CVE-2006-4855? In plain terms

An attacker has to be already on the device without logging in. If it works, the attacker can take it offline.

### The official description

The \Device\SymEvent driver in Symantec Norton Personal Firewall 2006 9.1.0.33, and other versions of Norton Personal Firewall, Internet Security, AntiVirus, SystemWorks, Symantec Client Security SCS 1.x, 2.x, 3.0, and 3.1, Symantec AntiVirus Corporate Edition SAVCE 8.x, 9.x, 10.0, and 10.1, Symantec pcAnywhere 11.5 only, and Symantec Host, allows local users to cause a denial of service (system crash) via invalid data, as demonstrated by calling DeviceIoControl to send the data.

### What kind of flaw is it?

- Unknown: Unknown

### How an attack on it works

- Where an attacker can be: Already on the device
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- What an attacker gets: Can take it offline

Severity vector: `AV:L/AC:L/Au:N/C:N/I:N/A:C`

## Is CVE-2006-4855 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.3%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 1.3%, 1.3%, 1.3%, 1.3%, 1.3%, 1.3%, 1.3%.

### Timeline

- 19 September 2006: Published
- 16 June 2026: Record last updated

### How Precursor Intelligence ranks it

CVE-2006-4855 scores **37 out of 100 (Low)**, with the action "Monitor".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2006-4855?

The published record lists 7 products.

- [Client Security](https://www.precursorintelligence.com/product/symantec/client_security) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 1.0, 1.0_build_8.01.9374, 1.0.0_b8.01.9378, 1.0.1, 1.0.1_build_8.01.425a-mr1, 1.0.1_build_8.01.429c-mr2, 1.0.1_build_8.01.434-mr3, 1.0.1_build_8.01.437, 1.0.1_build_8.01.446-mr4, 1.0.1_build_8.01.457-mr5, 1.0.1_build_8.01.460-mr6, 1.0.1_build_8.01.464-mr7, 1.0.1_build_8.01.471-mr8, 1.0.1_build_8.01.501-mr9, 1.1, 1.1_stm_b8.1.0.825a, 1.1.1, 1.1.1_build_393, 1.1.1_mr1_build_8.1.1.314a, 1.1.1_mr2_build_8.1.1.319, 1.1.1_mr3_build_8.1.1.323, 1.1.1_mr4_build_8.1.1.329, 1.1.1_mr5_build_8.1.1.336, 1.1.1_mr6_b8.1.1.266, 2.0, 2.0_scf_7.1, 2.0_stm_build_9.0.0.338, 2.0.1_build_9.0.1.1000-mr1, 2.0.2_build_9.0.2.1000-mr2, 2.0.3_build_9.0.3.1000-mr3, 2.0.5_build_1100, 3.0, 3.1
- [Norton Antivirus](https://www.precursorintelligence.com/product/symantec/norton_antivirus) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 2.1, 8.0, 8.0.1, 8.0.1.425a, 8.0.1.425c, 8.0.1.501, 8.0.1.9374, 8.0.1.9378, 8.1, 8.1.0.825a, 8.1.1, 8.1.1_build8.1.1.314a, 8.1.1_build393, 8.1.1.319, 8.1.1.323, 8.1.1.329, 8.1.1.366, 8.1.1.377, 8.01.434, 8.01.437, 8.01.446, 8.01.457, 8.01.460, 8.01.464, 8.01.471, 9.0, 9.0.0.338, 9.0.1.1.1000, 9.0.2.1000, 9.0.3.1000, 9.0.4, 9.0.5, 9.0.5.1100, 10.0, 10.0.2.2000, 10.0.2.2001, 10.0.2.2002, 10.0.2.2010, 10.0.2.2011, 10.0.2.2020 and 7 more
- [Norton System Works](https://www.precursorintelligence.com/product/symantec/norton_system_works) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 2003_professional_edition, 2004, 2004_professional_edition, 2005, 2005_premier, 2006
- [Norton Internet Security](https://www.precursorintelligence.com/product/symantec/norton_internet_security) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 2003, 2004, 2005, 2006, 2007
- [Norton Personal Firewall](https://www.precursorintelligence.com/product/symantec/norton_personal_firewall) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 2003, 2004, 2005, 2006
- [Host IDS](https://www.precursorintelligence.com/product/symantec/host_ids) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): all versions
- [Pcanywhere](https://www.precursorintelligence.com/product/symantec/pcanywhere) by [Symantec](https://www.precursorintelligence.com/vendors/symantec) (Application): 11.5

## How do I fix CVE-2006-4855?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [secunia.com](http://secunia.com/advisories/21938) (Vendor advisory)
- [matousec.com](http://www.matousec.com/info/advisories/Norton-Insufficient-validation-of-SymEvent-driver-input-buffer.php) (Vendor advisory)
- [vupen.com](http://www.vupen.com/english/advisories/2006/3636) (Vendor advisory)
- [securityreason.com](http://securityreason.com/securityalert/1591)
- [securityresponse.symantec.com](http://securityresponse.symantec.com/avcenter/security/Content/2006.09.20a.html)
- [securitytracker.com](http://securitytracker.com/id?1016889)
- [securitytracker.com](http://securitytracker.com/id?1016892)
- [securitytracker.com](http://securitytracker.com/id?1016893)
- [securitytracker.com](http://securitytracker.com/id?1016894)
- [securitytracker.com](http://securitytracker.com/id?1016895)
- [securitytracker.com](http://securitytracker.com/id?1016896)
- [securitytracker.com](http://securitytracker.com/id?1016897)
- [securitytracker.com](http://securitytracker.com/id?1016898)
- [securityfocus.com](http://www.securityfocus.com/archive/1/446111/100/0/threaded)
- [securityfocus.com](http://www.securityfocus.com/bid/20051) (Exploit)
- [exchange.xforce.ibmcloud.com](https://exchange.xforce.ibmcloud.com/vulnerabilities/28960)

## Questions

### What is CVE-2006-4855?

CVE-2006-4855 is a medium-severity flaw in Client Security from Symantec, published on 19 September 2006. An attacker has to be already on the device without logging in. If it works, the attacker can take it offline.

### How serious is CVE-2006-4855?

It scores 4.9 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2006-4855 is 37 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2006-4855 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.3%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2006-4855 affect?

For Client Security from Symantec: 1.0, 1.0_build_8.01.9374, 1.0.0_b8.01.9378, 1.0.1, 1.0.1_build_8.01.425a-mr1, 1.0.1_build_8.01.429c-mr2 and 27 more. The record lists 7 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2006-4855?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2006-4855 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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