File downloads encoded with "blob:" and "data:" URL elements bypassed normal file download checks though the Phishing and Malware Protection
File downloads encoded with "blob:" and "data:" URL elements bypassed normal file download checks though the Phishing and Malware Protection feature and its block lists of suspicious sites and files. This would allow malicious sites to lure users into downloading executables that would otherwise be detected as suspicious. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.
- Published
- Jun 11, 2018
- Updated
- Jun 16, 2026
- EPSS
- 1.2% · 67th percentile
- CWE
- CWE-20
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.2%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server aus | cpe:2.3:o:redhat:enterprise_linux_server_aus |
| redhat | enterprise linux server eus | cpe:2.3:o:redhat:enterprise_linux_server_eus |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
| mozilla | firefox | cpe:2.3:a:mozilla:firefox |
| mozilla | thunderbird | cpe:2.3:a:mozilla:thunderbird |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux7.0
- debian debian linux8.0
- debian debian linux9.0
- mozilla firefoxbefore 52.4.0
- mozilla firefoxbefore 56.0
- mozilla thunderbirdbefore 52.4.0
- redhat enterprise linux desktop6.0
- redhat enterprise linux desktop7.0
- redhat enterprise linux server6.0
- redhat enterprise linux server7.0
- redhat enterprise linux server aus7.4
- redhat enterprise linux server eus7.4
- redhat enterprise linux server eus7.5
- redhat enterprise linux workstation6.0
- redhat enterprise linux workstation7.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.
Mozilla Firefox
- unspecified and later · before 56affected
Mozilla Firefox ESR
- unspecified and later · before 52.4affected
Mozilla Thunderbird
- unspecified and later · before 52.4affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | firefox-esr | before 52.4.0esr-2 | 52.4.0esr-2 |
| Debian:12 | thunderbird | before 1:52.4.0-1 | 1:52.4.0-1 |
| Debian:7 | firefox-esr | before 52.4.0esr-2~deb7u1 | 52.4.0esr-2~deb7u1 |
| Debian:7 | thunderbird | before 1:52.4.0-1~deb7u1 | 1:52.4.0-1~deb7u1 |
| Debian:8 | firefox-esr | before 52.4.0esr-1~deb8u1 | 52.4.0esr-1~deb8u1 |
| Debian:8 | thunderbird | before 1:52.4.0-1~deb8u1 | 1:52.4.0-1~deb8u1 |
| Debian:9 | firefox-esr | before 52.4.0esr-1~deb9u1 | 52.4.0esr-1~deb9u1 |
| Debian:9 | thunderbird | before 1:52.4.0-1~deb9u1 | 1:52.4.0-1~deb9u1 |
| Red Hat:enterprise_linux:6::client | firefox | before 0:52.4.0-1.el6_9 | 0:52.4.0-1.el6_9 |
| Red Hat:enterprise_linux:6::client | firefox-debuginfo | before 0:52.4.0-1.el6_9 | 0:52.4.0-1.el6_9 |
| Red Hat:enterprise_linux:6::client | thunderbird | before 0:52.4.0-2.el6_9 | 0:52.4.0-2.el6_9 |
| Red Hat:enterprise_linux:6::client | thunderbird-debuginfo | before 0:52.4.0-2.el6_9 | 0:52.4.0-2.el6_9 |
| Red Hat:enterprise_linux:7::client | firefox | before 0:52.4.0-1.el7_4 | 0:52.4.0-1.el7_4 |
| Red Hat:enterprise_linux:7::client | firefox-debuginfo | before 0:52.4.0-1.el7_4 | 0:52.4.0-1.el7_4 |
| Red Hat:enterprise_linux:7::client | thunderbird | before 0:52.4.0-2.el7_4 | 0:52.4.0-2.el7_4 |
| Red Hat:enterprise_linux:7::client | thunderbird-debuginfo | before 0:52.4.0-2.el7_4 | 0:52.4.0-2.el7_4 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | mozilla-nss | before 3.29.5-47.6.1 | 3.29.5-47.6.1 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | MozillaFirefox | before 52.4.0esr-72.13.2 | 52.4.0esr-72.13.2 |
| SUSE:OpenStack Cloud 6 | mozilla-nss | before 3.29.5-58.3.1 | 3.29.5-58.3.1 |
| SUSE:OpenStack Cloud 6 | MozillaFirefox | before 52.4.0esr-109.6.2 | 52.4.0esr-109.6.2 |
| SUSE:Package Hub 12 | MozillaThunderbird | before 52.4.0-45.1 | 52.4.0-45.1 |
Same product
redhat: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-5375JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption attacks.49Plan
- CVE-2018-14649It was found that ceph-isci-cli package as shipped by Red Hat Ceph Storage 2 and 3 is using python-werkzeug in debug shell mode.43Plan
- CVE-2016-7050SerializableProvider in RESTEasy in Red Hat Enterprise Linux Desktop 7, Red Hat Enterprise Linux HPC Node 7, Red Hat Enterprise Linux Server41Plan
- CVE-2010-5325Heap-based buffer overflow in the unhtmlify function in foomatic-rip in foomatic-filters before 4.0.6 allows remote attackers to cause a den41Plan
- CVE-2018-5156A vulnerability can occur when capturing a media stream when the media source type is changed as the capture is occurring.40Plan
- CVE-2018-12378A use-after-free vulnerability can occur when an IndexedDB index is deleted while still in use by JavaScript code that is providing payload 40Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:firefox-esr | 52.4.0esr-2 · Debian:12 | Package registry (OSV) |
| debian:thunderbird | 1:52.4.0-1 · Debian:12 | Package registry (OSV) |
| red hat:firefox | 0:52.4.0-1.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:firefox-debuginfo | 0:52.4.0-1.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:thunderbird | 0:52.4.0-2.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:thunderbird-debuginfo | 0:52.4.0-2.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| suse:mozilla-nss | 3.29.5-58.3.1 · SUSE:OpenStack Cloud 6 | Package registry (OSV) |
| suse:MozillaFirefox | 52.4.0esr-109.6.2 · SUSE:OpenStack Cloud 6 | Package registry (OSV) |
| suse:MozillaThunderbird | 52.4.0-45.1 · SUSE:Package Hub 12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.securityfocus.com/bid/101059
- www.securitytracker.com/id/1039465
- access.redhat.com/errata/RHSA-2017:2831
- access.redhat.com/errata/RHSA-2017:2885
- bugzilla.mozilla.org/show_bug.cgi?id=1376036
- lists.debian.org/debian-lts-announce/2017/11/msg00000.html
- security.gentoo.org/glsa/201803-14
- www.debian.org/security/2017/dsa-3987
- www.debian.org/security/2017/dsa-4014
- www.mozilla.org/security/advisories/mfsa2017-21/
- www.mozilla.org/security/advisories/mfsa2017-22/
- www.mozilla.org/security/advisories/mfsa2017-23/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.