# What is CVE-2009-2408? > CVE-2009-2408 is a medium-severity flaw (CVSS 5.9) in Firefox from Mozilla, published on 30 July 2009. 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 5.7%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2009-2408 ## 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:** 24 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.9 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:** 5.7% (latest exploit-likelihood forecast) - **Published:** 30 July 2009 - **Record last updated:** 16 June 2026 - **Main product:** Firefox from Mozilla - **Affected products:** 9 ## What is CVE-2009-2408? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change data. ### The official description Mozilla Network Security Services (NSS) before 3.12.3, Firefox before 3.0.13, Thunderbird before 2.0.0.23, and SeaMonkey before 1.1.18 do not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority. NOTE: this was originally reported for Firefox before 3.5. ### What kind of flaw is it? - CWE-295: Improper Certificate Validation ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Hard: conditions must line up - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can change data Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N` ## Is CVE-2009-2408 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 5.7%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 5.0%, 5.7%, 5.7%, 5.7%, 5.7%, 5.7%, 5.7%. ### Timeline - 30 July 2009: Published - 16 June 2026: Record last updated ### How Precursor Intelligence ranks it CVE-2009-2408 scores **24 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-2009-2408? The published record lists 9 products. Versions are as published: "before 3.0.13" means every version up to, but not including, 3.0.13. - [Firefox](https://www.precursorintelligence.com/product/mozilla/firefox) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): before 3.0.13 - [Ubuntu Linux](https://www.precursorintelligence.com/product/canonical/ubuntu_linux) by [Canonical](https://www.precursorintelligence.com/vendors/canonical) (Operating system): 8.04, 8.10, 9.04 - [Linux Enterprise](https://www.precursorintelligence.com/product/suse/linux_enterprise) by [Suse](https://www.precursorintelligence.com/vendors/suse) (Operating system): 10.0, 11.0 - [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 5.0 - [Linux Enterprise Server](https://www.precursorintelligence.com/product/suse/linux_enterprise_server) by [Suse](https://www.precursorintelligence.com/vendors/suse) (Operating system): 9 - [Network Security Services](https://www.precursorintelligence.com/product/mozilla/network_security_services) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): before 3.12.3 - [Opensuse](https://www.precursorintelligence.com/product/opensuse/opensuse) by [Opensuse](https://www.precursorintelligence.com/vendors/opensuse) (Operating system): 10.3 to 11.1 - [Seamonkey](https://www.precursorintelligence.com/product/mozilla/seamonkey) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): before 1.1.18 - [Thunderbird](https://www.precursorintelligence.com/product/mozilla/thunderbird) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): before 2.0.0.23 ## How do I fix CVE-2009-2408? 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/36088) (Broken link, Vendor advisory) - [secunia.com](http://secunia.com/advisories/36125) (Broken link, Vendor advisory) - [secunia.com](http://secunia.com/advisories/36139) (Broken link, Vendor advisory) - [secunia.com](http://secunia.com/advisories/36157) (Broken link, Vendor advisory) - [secunia.com](http://secunia.com/advisories/36434) (Broken link, Vendor advisory) - [mozilla.org](http://www.mozilla.org/security/announce/2009/mfsa2009-42.html) (Vendor advisory) - [vupen.com](http://www.vupen.com/english/advisories/2009/2085) (Broken link, Vendor advisory) - [isc.sans.org](http://isc.sans.org/diary.html?storyid=7003) (Broken link) - [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2009-11/msg00004.html) (Mailing list) - [marc.info](http://marc.info/?l=oss-security&m=125198917018936&w=2) (Mailing list) - [osvdb.org](http://osvdb.org/56723) (Broken link) - [secunia.com](http://secunia.com/advisories/36669) (Broken link) - [secunia.com](http://secunia.com/advisories/37098) (Broken link) - [sunsolve.sun.com](http://sunsolve.sun.com/search/document.do?assetkey=1-77-1021030.1-1) (Broken link) - [debian.org](http://www.debian.org/security/2009/dsa-1874) (Mailing list) - [mandriva.com](http://www.mandriva.com/security/advisories?name=MDVSA-2009:197) (Broken link) - [mandriva.com](http://www.mandriva.com/security/advisories?name=MDVSA-2009:216) (Broken link) - [mandriva.com](http://www.mandriva.com/security/advisories?name=MDVSA-2009:217) (Broken link) - [novell.com](http://www.novell.com/linux/security/advisories/2009_48_firefox.html) (Broken link) - [openldap.org](http://www.openldap.org/devel/cvsweb.cgi/libraries/libldap/tls_m.c.diff?r1=1.8&r2=1.11&f=h) (Broken link) - [redhat.com](http://www.redhat.com/support/errata/RHSA-2009-1207.html) (Broken link) - [redhat.com](http://www.redhat.com/support/errata/RHSA-2009-1432.html) (Broken link) - [securitytracker.com](http://www.securitytracker.com/id?1022632) (Broken link, Third-party advisory, Vulnerability database) - [ubuntu.com](http://www.ubuntu.com/usn/usn-810-1) (Third-party advisory) - [vupen.com](http://www.vupen.com/english/advisories/2009/3184) (Broken link) - [wired.com](http://www.wired.com/threatlevel/2009/07/kaminsky/) (Press/media coverage) - [bugzilla.redhat.com](https://bugzilla.redhat.com/show_bug.cgi?id=510251) (Issue tracking) - [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10751) (Broken link) - [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A8458) (Broken link) - [usn.ubuntu.com](https://usn.ubuntu.com/810-2/) (Broken link) ## Questions ### What is CVE-2009-2408? CVE-2009-2408 is a medium-severity flaw in Firefox from Mozilla, published on 30 July 2009. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change data. ### How serious is CVE-2009-2408? It scores 5.9 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2009-2408 is 24 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-2009-2408 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 5.7%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2009-2408 affect? For Firefox from Mozilla: before 3.0.13. The record lists 9 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2009-2408? 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-2009-2408 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. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact