VulnerabilityAnalyzed

CVE-2010-3765

Mozilla Multiple Products Remote Code Execution Vulnerability

KEVEXPLOIT ×4 ✓CRITICAL 9.8EPSS 83.2%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 27 October 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

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.

CVSS 3.1: 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 83.16% probability · 100th percentile
Public exploits: 4 in Exploit-DB · verified · first 28 October 2010
CISA KEV: Listed 6 October 2025 · due 27 October 2025
Weakness: CWE-119
Affected: mozilla/firefox · mozilla/thunderbird · mozilla/seamonkey
Source: cve@mitre.org

EPSS trend

EPSS 83.2% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

CISA notes

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://www.mozilla.org/en-US/security/advisories/mfsa2010-73 ; https://nvd.nist.gov/vuln/detail/CVE-2010-3765

Public exploits (4)

Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.

EDB-ID	Title	Type	Published	Verified
EDB-16509 source ↗	Mozilla Firefox - Interleaving 'document.write' / 'appendChild' (Metasploit)windows · Metasploit	remote	22 February 2011	yes
EDB-15352 source ↗	Mozilla Firefox 3.6.8 < 3.6.11 - Interleaving 'document.write' / 'appendChild' Remote Overflowwindows · anonymous	remote	29 October 2010	yes
EDB-15342 source ↗	Mozilla Firefox - Simplified Memory Corruption (PoC)multiple · extraexploit	dos	28 October 2010	yes
EDB-15341 source ↗	Mozilla Firefox - Interleaving 'document.write' / 'appendChild' Denial of Servicemultiple · Daniel Veditz	dos	28 October 2010	yes

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_firefoxBroken Link
http://isc.sans.edu/diary.html?storyid=9817Press/Media Coverage
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/050233.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050061.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050077.htmlThird Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2010-October/050154.htmlThird Party Advisory
http://norman.com/about_norman/press_center/news_archive/2010/129223/en?utm_source=twitterfeed&utm_medium=twitterProduct
http://secunia.com/advisories/41761Vendor Advisory
http://secunia.com/advisories/41965Vendor Advisory
http://secunia.com/advisories/41966Vendor Advisory
http://secunia.com/advisories/41969Vendor Advisory
http://secunia.com/advisories/41975Vendor Advisory
http://secunia.com/advisories/42003Vendor Advisory
http://secunia.com/advisories/42008Vendor Advisory
http://secunia.com/advisories/42043Vendor Advisory
http://secunia.com/advisories/42867Vendor Advisory
http://slackware.com/security/viewer.php?l=slackware-security&y=2010&m=slackware-security.556706Third Party Advisory
http://support.avaya.com/css/P8/documents/100114329Third Party Advisory
http://support.avaya.com/css/P8/documents/100114335Third Party Advisory
http://www.debian.org/security/2010/dsa-2124Third Party Advisory
http://www.exploit-db.com/exploits/15341Exploit
http://www.exploit-db.com/exploits/15342Exploit
http://www.exploit-db.com/exploits/15352Exploit
http://www.mandriva.com/security/advisories?name=MDVSA-2010:213Third Party Advisory
http://www.mandriva.com/security/advisories?name=MDVSA-2010:219Third Party Advisory
http://www.mozilla.org/security/announce/2010/mfsa2010-73.htmlThird 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.htmlThird Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.