CVE-2010-3765
CriticalExploitedPublic exploitFirefox race condition flaw (MFSA 2010-73)
Published Oct 28, 2010 · Updated Mar 9, 2026
Key Facts
Patch immediately- CVE-2010-3765 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Firefox (Mozilla), Seamonkey (Mozilla), Thunderbird (Mozilla) and 21 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Oct 27, 2010. Public exploit code is available.
- EPSS estimates a 83% probability of exploitation in the next 30 days.
- Fixed versions are available, including Firefox 0:3.6.11-4.el4_8, Firefox 0:3.6.12-1.el6_0, firefox-esr 128.5.1-1.1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
83%
Higher than 99.6% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2010-3765 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Oct 6, 2025 | Oct 27, 2025 | Not reported |
| Industry KEV feed | Oct 27, 2010 | Oct 27, 2025 | Not reported |
| CIRCL KEV | Oct 27, 2010 | Oct 27, 2025 | Not reported |
| ENISA EUVD | Oct 6, 2025 | n/a | Not reported |
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.
Affected Products
88 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| FirefoxMozilla | 3.5, 3.5.1, 3.5.10, 3.5.11, 3.5.12, 3.5.13, 3.5.14, 3.5.2 | 0:3.6.11-4.el4_8 |
| SeamonkeyMozilla | 2.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7 | 0:1.0.9-0.62.el3 |
| ThunderbirdMozilla | 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.0.5, 3.0.6, 3.0.7, 3.0.8 | 0:1.5.0.12-33.el4 |
| xulrunnerdebian | See advisory | 1.9.0.19-6 |
| xulrunner-develoracle | See advisory | 1.9.2.11-4.0.1.el5_5 |
Patched Releases
Firefox
0:3.6.11-4.el4_8, 0:3.6.12-1.el6_0
firefox-esr
128.5.1-1.1
firefox-esr-branding-upstream
128.5.1-1.1
firefox-esr-translations-common
128.5.1-1.1
firefox-esr-translations-other
128.5.1-1.1
MozillaFirefox
50.1.0-1.1
MozillaFirefox-branding-upstream
50.1.0-1.1
MozillaFirefox-buildsymbols
50.1.0-1.1
MozillaFirefox-devel
50.1.0-1.1
MozillaFirefox-translations-common
50.1.0-1.1
MozillaFirefox-translations-other
50.1.0-1.1
MozillaThunderbird
45.5.1-1.1
MozillaThunderbird-buildsymbols
45.5.1-1.1
MozillaThunderbird-devel
45.5.1-1.1
MozillaThunderbird-translations-common
45.5.1-1.1
MozillaThunderbird-translations-other
45.5.1-1.1
Seamonkey
0:1.0.9-0.62.el3, 0:1.0.9-65.el4_8, 2.40-6.1
seamonkey-dom-inspector
2.40-6.1
seamonkey-irc
2.40-6.1
seamonkey-translations-common
2.40-6.1
seamonkey-translations-other
2.40-6.1
Thunderbird
0:1.5.0.12-33.el4, 0:2.0.0.24-10.el5_5, 0:3.1.6-1.el6_0
xulrunner
0:1.9.2.11-4.el5_5, 0:1.9.2.12-1.el6_0, 1.9.0.19-6, 1.9.2.11-4.0.1.el5_5
xulrunner-devel
1.9.2.11-4.0.1.el5_5
Timeline
Added to Industry KEV feed
Oct 27, 2010
Added to CIRCL KEV
Oct 27, 2010
Publicly disclosed
Oct 28, 2010
Added to CISA KEV
Oct 6, 2025
Added to ENISA EUVD
Oct 6, 2025
Last updated
Mar 9, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisoryhttp://blog.mozilla.com/security/2010/10/26/critical-vulnerability-in-firefox-3-5-and-firefox-3-6/
- advisoryFEDORA-2010-17105
- advisoryFEDORA-2010-16883
- advisoryFEDORA-2010-16897
- advisoryFEDORA-2010-16885
FAQ
Common Questions.
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, in…
Affected: Firefox (Mozilla) versions 3.5, 3.5.1, 3.5.10, 3.5.11, 3.5.12, 3.5.13, 3.5.14, 3.5.2; Seamonkey (Mozilla) versions 2.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7; Thunderbird (Mozilla) versions 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.0.5, 3.0.6, 3.0.7, 3.0.8, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Oct 27, 2010.
Yes. It was added on Oct 6, 2025 with a federal remediation due date of Oct 27, 2025.
Public exploit code is available.
Fixed versions are available, including Firefox 0:3.6.11-4.el4_8, Firefox 0:3.6.12-1.el6_0, firefox-esr 128.5.1-1.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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