Mozilla Firefox Security Feature Bypass
CVE-2015-4495 is a high-severity origin validation error vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 39.0.3, 38.1.1 as the first without the flaw, so updating Firefox to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on May 25, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Firefox to 39.0.3 or 38.1.1, whichever matches your release line, or a later version.
- Update Firefox OS to 2.2 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on mozilla.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Mozilla | Firefox | before 39.0.3; 38.0 up to, but not including, 38.1.1 | 39.0.3, 38.1.1 |
| Mozilla | Firefox OS | before 2.2 | 2.2 |
| Oracle | Solaris | 11.3 | Not stated |
| Canonical | Ubuntu Linux | 12.04; 14.04; 15.04 | Not stated |
| Red Hat | Enterprise Linux Desktop | 5.0; 6.0; 7.0 | Not stated |
| Red Hat | Enterprise Linux EUS | 6.7; 7.1; 7.2; 7.3; 7.4; 7.5; 7.6; 7.7 | Not stated |
| Red Hat | Enterprise Linux Server | 5.0; 6.0; 7.0 | Not stated |
| Red Hat | Enterprise Linux Server AUS | 7.3; 7.4; 7.6; 7.7 | Not stated |
| Red Hat | Enterprise Linux Server TUS | 7.3; 7.6; 7.7 | Not stated |
| Red Hat | Enterprise Linux Workstation | 5.0; 6.0; 7.0 | Not stated |
| SUSE | Linux Enterprise Debuginfo | 11 | Not stated |
| openSUSE | Opensuse | 13.1; 13.2 | Not stated |
| SUSE | Linux Enterprise Desktop | 11; 12 | Not stated |
| SUSE | Linux Enterprise Server | 11; 12 | Not stated |
| SUSE | Linux Enterprise Software Development Kit | 11; 12 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 4.3 | Medium | NVD |
Official description
The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypass the Same Origin Policy, and read arbitrary files or gain privileges, via vectors involving crafted JavaScript code and a native setter, as exploited in the wild in August 2015.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
Third-party and government advisories
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00009.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00010.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00014.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00015.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-security-announce/2015-08/msg00021.htmlMailing List, Third Party Advisory
- lists.opensuse.org/opensuse-security-announce/2015-09/msg00016.htmlMailing List, Third Party Advisory
- rhn.redhat.com/errata/RHSA-2015-1581.htmlThird Party Advisory
- ubuntu.com/usn/USN-2707-1Third Party Advisory
- security.gentoo.org/glsa/201512-10Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-4495US Government Resource
Technical write-ups (may include proof of concept)
- exploit-db.com/exploits/37772/Exploit, Third Party Advisory, VDB Entry
Other references
- bugzilla.mozilla.org/show_bug.cgi?id=1178058Issue Tracking
- bugzilla.mozilla.org/show_bug.cgi?id=1179262Issue Tracking
Other vulnerabilities in Firefox
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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