Mozilla: Errors in the handling of CORS preflight request headers (MFSA 2015-111)
Published Sep 24, 2015
6.4
MEDIUMCVSS 2.0
EPSS 3.09%
Description
Mozilla Firefox before 41.0 and Firefox ESR 38.x before 38.3 allow remote attackers to bypass CORS preflight protection mechanisms by leveraging (1) duplicate cache-key generation or (2) retrieval of a value from an incorrect HTTP Access-Control-* response header.
Affected products
No data.
Configuration 1
No data.
Red Hat Enterprise Linux 5
firefox-0:38.3.0-2.el5_11
Fixed · RHSA-2015:1834
Red Hat Enterprise Linux 5
thunderbird-0:38.3.0-1.el5_11
Fixed · RHSA-2015:1852
Red Hat Enterprise Linux 6
firefox-0:38.3.0-2.el6_7
Fixed · RHSA-2015:1834
Red Hat Enterprise Linux 6
thunderbird-0:38.3.0-1.el6_7
Fixed · RHSA-2015:1852
Red Hat Enterprise Linux 7
firefox-0:38.3.0-2.ael7b_1
Fixed · RHSA-2015:1834
Red Hat Enterprise Linux 7
thunderbird-0:38.3.0-1.ael7b_1
Fixed · RHSA-2015:1852
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | firefox-0:38.3.0-2.el5_11 | Fixed | RHSA-2015:1834 |
| Red Hat Enterprise Linux 5 | thunderbird-0:38.3.0-1.el5_11 | Fixed | RHSA-2015:1852 |
| Red Hat Enterprise Linux 6 | firefox-0:38.3.0-2.el6_7 | Fixed | RHSA-2015:1834 |
| Red Hat Enterprise Linux 6 | thunderbird-0:38.3.0-1.el6_7 | Fixed | RHSA-2015:1852 |
| Red Hat Enterprise Linux 7 | firefox-0:38.3.0-2.ael7b_1 | Fixed | RHSA-2015:1834 |
| Red Hat Enterprise Linux 7 | thunderbird-0:38.3.0-1.ael7b_1 | Fixed | RHSA-2015:1852 |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:N/AC:L/Au:N/C:P/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 1, 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 (12 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 3.09% (0.03095) | 87.28th | v5 (v2026.06.15) |
| Jun 15, 2026 | 3.04% (0.03036) | 85.74th | v5 (v2026.06.15) |
| Mar 30, 2025 | 0.59% (0.00592) | 66.69th | v4 (v2025.03.14) |
| Mar 29, 2025 | 1.69% (0.01687) | 70.80th | v4 (v2025.03.14) |
| Mar 17, 2025 | 0.59% (0.00592) | 67.36th | v4 (v2025.03.14) |
| Dec 12, 2024 | 1.11% (0.01106) | 85.12th | v3 (v2023.03.01) |
| Jul 14, 2024 | 1.11% (0.01106) | 84.63th | v3 (v2023.03.01) |
| May 7, 2024 | 1.56% (0.01561) | 87.14th | v3 (v2023.03.01) |
| Mar 7, 2023 | 1.56% (0.01561) | 85.14th | v3 (v2023.03.01) |
| Mar 6, 2023 | 4.36% (0.04358) | 88.02th | v2 (v2022.01.01) |
| Apr 1, 2022 | 4.36% (0.04358) | 86.83th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.36% (0.04358) | 70.59th | v2 (v2022.01.01) |
References (26)
- http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00000.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00003.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00004.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00005.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2015-10/msg00007.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2015-11/msg00025.html vendor-advisoryx_refsource_SUSE
- http://rhn.redhat.com/errata/RHSA-2015-1834.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2015-1852.html vendor-advisoryx_refsource_REDHAT
- http://www.debian.org/security/2015/dsa-3365 vendor-advisoryx_refsource_DEBIAN
- http://www.mozilla.org/security/announce/2015/mfsa2015-111.html x_refsource_CONFIRMVendor Advisory
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html x_refsource_CONFIRM
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html x_refsource_CONFIRM
- http://www.securityfocus.com/bid/76816 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id/1033640 vdb-entryx_refsource_SECTRACK
- http://www.ubuntu.com/usn/USN-2743-1 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-2743-2 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-2743-3 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-2743-4 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-2754-1 vendor-advisoryx_refsource_UBUNTU
- https://access.redhat.com/security/cve/CVE-2015-4520 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1200856 x_refsource_CONFIRM
- https://bugzilla.mozilla.org/show_bug.cgi?id=1200869 x_refsource_CONFIRM
- https://bugzilla.redhat.com/show_bug.cgi?id=1265781 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2015-4520
- https://www.cve.org/CVERecord?id=CVE-2015-4520
- https://www.mozilla.org/en-US/security/advisories/mfsa2015-111/
Change history (0)
No recorded changes yet.