Mozilla: Possible XSS via HTTP 0.9 errors and content-sniffing
Published Jun 2, 2021
6.1
MEDIUMCVSS 3.1
EPSS 0.76%
Description
Cross-site scripting (XSS) vulnerability in Mozilla Firefox before 3.6.24 and 4.x through 7 allows remote attackers to inject arbitrary web script or HTML via vectors involving HTTP 0.9 errors, non-default ports, and content-sniffing.
Affected products
No data.
No data.
Red Hat Enterprise Linux 4
firefox
Affected
Red Hat Enterprise Linux 4
seamonkey
Affected
Red Hat Enterprise Linux 4
thunderbird
Affected
Red Hat Enterprise Linux 5
firefox
Affected
Red Hat Enterprise Linux 5
thunderbird
Affected
Red Hat Enterprise Linux 6
firefox
Affected
Red Hat Enterprise Linux 6
thunderbird
Affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 4 | firefox | Affected | n/a |
| Red Hat Enterprise Linux 4 | seamonkey | Affected | n/a |
| Red Hat Enterprise Linux 4 | thunderbird | Affected | n/a |
| Red Hat Enterprise Linux 5 | firefox | Affected | n/a |
| Red Hat Enterprise Linux 5 | thunderbird | Affected | n/a |
| Red Hat Enterprise Linux 6 | firefox | Affected | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:N/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (11 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 0.76% (0.00761) | 53.72th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.76% (0.00761) | 50.35th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.26% (0.00259) | 47.29th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.11% (0.00115) | 46.80th | v3 (v2023.03.01) |
| Jun 14, 2024 | 0.11% (0.00115) | 45.33th | v3 (v2023.03.01) |
| Feb 16, 2024 | 0.11% (0.00112) | 43.32th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.10% (0.00104) | 40.73th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.05% (0.01055) | 52.13th | v2 (v2022.01.01) |
| Sep 17, 2022 | 1.05% (0.01055) | 50.47th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.05% (0.01055) | 48.43th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.05% (0.01055) | 27.52th | v2 (v2022.01.01) |
References (5)
- https://access.redhat.com/security/cve/CVE-2011-3656 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=667907 x_refsource_MISCIssue TrackingVendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=751935 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2011-3656
- https://www.cve.org/CVERecord?id=CVE-2011-3656
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2011-3656 | Vendor Advisory | |
| https://bugzilla.mozilla.org/show_bug.cgi?id=667907 | x_refsource_MISCIssue TrackingVendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=751935 | Issue Tracking | |
| https://nvd.nist.gov/vuln/detail/CVE-2011-3656 | ||
| https://www.cve.org/CVERecord?id=CVE-2011-3656 |
Change history (0)
No recorded changes yet.