Is CVE-2010-3765 being actively exploited?

Yes. CVE-2010-3765 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on October 6, 2025.

What is the CVSS score for CVE-2010-3765?

CVE-2010-3765 has a CVSS 3.1 base score of 9.8 (CRITICAL).

CVE-2010-3765

CRITICAL · CVSS 9.8CISA KEV: actively exploitedEPSS 83.2%EU EUVD: exploited

Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x before 2.0.10, when JavaScript is enabled, allows remote attackers to execute arbitrary code via vectors related to nsCSSFrameConstructor::ContentAppended, the appendChild method, incorrect index tracking, and the creation of multiple frames, which triggers memory corruption, as exploited in the wild in October 2010 by the Belmoo malware.

Key facts

CVSS score: 9.8 (v3.1)
Severity: CRITICAL
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-119
EPSS score: 83.2% (100th percentile)
In CISA KEV: Yes, added October 6, 2025
In EU EUVD: Yes (EUVD-2010-3744)
Published: October 28, 2010
NVD last modified: June 16, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Mozilla Multiple Products Remote Code Execution Vulnerability

Added to the KEV catalog on October 6, 2025; federal remediation due October 27, 2025.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2010-3744 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on October 22, 2025.

View on the EU Vulnerability Database

Affected products

mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / firefox
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / seamonkey
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird
mozilla / thunderbird

and 6 more…

References

http://blog.mozilla.com/security/2010/10/26/critical-vulnerability-in-firefox-3-5-and-firefox-3-6/(Vendor Advisory)
http://blogs.sun.com/security/entry/multiple_vulnerabilities_in_mozilla_firefox(Broken Link)
http://isc.sans.edu/diary.html?storyid=9817(Press/Media Coverage)
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/050233.html(Third Party Advisory)
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050061.html(Third Party Advisory)
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050077.html(Third Party Advisory)
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050154.html(Third Party Advisory)
http://norman.com/about_norman/press_center/news_archive/2010/129223/en?utm_source=twitterfeed&utm_medium=twitter(Product)
http://secunia.com/advisories/41761(Vendor Advisory)
http://secunia.com/advisories/41965(Vendor Advisory)
http://secunia.com/advisories/41966(Vendor Advisory)
http://secunia.com/advisories/41969(Vendor Advisory)
http://secunia.com/advisories/41975(Vendor Advisory)
http://secunia.com/advisories/42003(Vendor Advisory)
http://secunia.com/advisories/42008(Vendor Advisory)
http://secunia.com/advisories/42043(Vendor Advisory)
http://secunia.com/advisories/42867(Vendor Advisory)
http://slackware.com/security/viewer.php?l=slackware-security&y=2010&m=slackware-security.556706(Third Party Advisory)
http://support.avaya.com/css/P8/documents/100114329(Third Party Advisory)
http://support.avaya.com/css/P8/documents/100114335(Third Party Advisory)
http://www.debian.org/security/2010/dsa-2124(Third Party Advisory)
http://www.exploit-db.com/exploits/15341(Exploit)
http://www.exploit-db.com/exploits/15342(Exploit)
http://www.exploit-db.com/exploits/15352(Exploit)
http://www.mandriva.com/security/advisories?name=MDVSA-2010:213(Third Party Advisory)
http://www.mandriva.com/security/advisories?name=MDVSA-2010:219(Third Party Advisory)
http://www.mozilla.org/security/announce/2010/mfsa2010-73.html(Third Party Advisory)
http://www.norman.com/about_norman/press_center/news_archive/2010/129223/(Broken Link)
http://www.norman.com/security_center/virus_description_archive/129146/(Broken Link)
http://www.redhat.com/support/errata/RHSA-2010-0808.html(Third Party Advisory)
http://www.redhat.com/support/errata/RHSA-2010-0809.html(Third Party Advisory)
http://www.redhat.com/support/errata/RHSA-2010-0810.html(Third Party Advisory)
http://www.redhat.com/support/errata/RHSA-2010-0861.html(Third Party Advisory)
http://www.redhat.com/support/errata/RHSA-2010-0896.html(Third Party Advisory)
http://www.securityfocus.com/bid/44425(Broken Link)
http://www.securitytracker.com/id?1024645(Broken Link)
http://www.securitytracker.com/id?1024650(Broken Link)
http://www.securitytracker.com/id?1024651(Broken Link)
http://www.ubuntu.com/usn/USN-1011-2(Third Party Advisory)
http://www.ubuntu.com/usn/USN-1011-3(Third Party Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

Query CVEs from your AI assistant

The CVE/NVD Explorer brain answers CVE questions directly inside Claude, ChatGPT, or any MCP assistant — always up to date, no setup. Add it once and stop pasting advisories into chat.

Add the CVE brain