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ExploitedIn CISA KEV

CVE-2010-3765

Exploitation confirmed. First attested on 2010-10-27 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2010-10-28
  • WeaknessCWE-119

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2010-10-2722:00Listed as exploited by GCVEGCVE
  2. 2010-10-2722:00Exploitation first reportedGCVE
  3. 2010-10-28CVE publishedNVD
  4. 2025-10-0403:55SSVC exploitation set to activeCISA-ADP
  5. 2025-10-06Added to the CISA KEV catalogCISA KEV
  6. 2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2010-3765?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2010-3765?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Mozilla firefox
BranchAffectedFixed in
3.5= 3.5no fix published
3.5= 3.5.1no fix published
3.5= 3.5.2no fix published
3.5= 3.5.3no fix published
3.5= 3.5.4no fix published
3.5= 3.5.5no fix published
3.5= 3.5.6no fix published
3.5= 3.5.7no fix published
3.5= 3.5.8no fix published
3.5= 3.5.9no fix published
3.5= 3.5.10no fix published
3.5= 3.5.11no fix published
Mozilla thunderbird
BranchAffectedFixed in
3.0= 3.0.1no fix published
3.0= 3.0.2no fix published
3.0= 3.0.3no fix published
3.0= 3.0.4no fix published
3.0= 3.0.5no fix published
3.0= 3.0.6no fix published
3.0= 3.0.7no fix published
3.0= 3.0.8no fix published
3.0= 3.0.9no fix published
3.1= 3.1.1no fix published
3.1= 3.1.2no fix published
3.1= 3.1.3no fix published
Mozilla seamonkey
BranchAffectedFixed in
2.0= 2.0no fix published
2.0= 2.0.1no fix published
2.0= 2.0.2no fix published
2.0= 2.0.3no fix published
2.0= 2.0.4no fix published
2.0= 2.0.5no fix published
2.0= 2.0.6no fix published
2.0= 2.0.7no fix published
2.0= 2.0.8no fix published
2.0= 2.0.9no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. CISA’s required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.due 2025-10-27

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

CISA Known Exploited Vulnerability

Date Added
2025-10-06
Patch Due Date
2025-10-27
Ransomware Use
Unknown
Required Action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Sources

  • CISA KEVKEV entry2025-10-06
  • GCVEexploitation2010-10-27
  • CISA-ADPSSVC decisionactive2025-10-04
  • OpenCVESSVC decisionactive—
  • CISA-ADPCVSS 3.19.82025-10-03
  • NVDCVSS 2.09.3read 2026-10-23
  • CISA-ADPweakness (CWE)CWE-1192025-10-03
  • NVDweakness (CWE)CWE-119read 2026-10-23
  • FIRST EPSSEPSS score83.2 %read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2010-10-28
Last Modified
2026-06-16
NVD status
Analyzed

Frequently asked questions

What is CVE-2010-3765?

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.

Is CVE-2010-3765 actively exploited?

Yes. CVE-2010-3765 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2025-10-27.

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

CVE-2010-3765 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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