CVE-2020-15659: Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0.
Noroxi assessment
Priority: Monitor (action score 36/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 2.3% (FIRST EPSS); higher than 84.1% of all records.
- Anyone who can reach it over the internet 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.
- Fixed version: firefox-esr (Alpine:v3.11) 68.11.0-r0; firefox (Alpine:v3.12) 79.0-r0; firefox-esr (Alpine:v3.12) 78.1.0-r0.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to firefox-esr (Alpine:v3.11) 68.11.0-r0; firefox (Alpine:v3.12) 79.0-r0; firefox-esr (Alpine:v3.12) 78.1.0-r0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.
- BDU:2021-00081
- DLA-2297-1
- DLA-2310-1
- DSA-4736-1
- DSA-4740-1
- openSUSE-SU-2020:1147-1
- openSUSE-SU-2020:1155-1
- openSUSE-SU-2020:1179-1
- openSUSE-SU-2020:1189-1
- openSUSE-SU-2020:1205-1
- RHSA-2020:3229
- RHSA-2020:3233
- RHSA-2020:3241
- RHSA-2020:3253
- RHSA-2020:3254
- RHSA-2020:3341
- RHSA-2020:3342
- RHSA-2020:3343
- RHSA-2020:3344
- RHSA-2020:3345
- Published
- Aug 10, 2020
- Updated
- Jun 16, 2026
- EPSS
- 2.3% · 84th percentile
- CWE
- CWE-787
Report tools
Action score
36
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.3%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| mozilla | firefox | cpe:2.3:a:mozilla:firefox |
| mozilla | firefox esr | cpe:2.3:a:mozilla:firefox_esr |
| mozilla | thunderbird | cpe:2.3:a:mozilla:thunderbird |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
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 79affected
Mozilla Firefox ESR
- unspecified and later · before 68.11affected
- unspecified and later · before 78.1affected
Mozilla Thunderbird
- unspecified and later · before 68.11affected
- unspecified and later · before 78.1affected
Affected versions · NVD (10)
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- canonical ubuntu linux20.04
- mozilla firefoxbefore 79.0
- mozilla firefox esr78.0 and later · before 78.1.0
- mozilla firefox esrbefore 68.11
- mozilla thunderbird78.0.1 and later · before 78.1.0
- mozilla thunderbirdbefore 68.11
- opensuse leap15.1
- opensuse leap15.2
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.11 | firefox-esr | before 68.11.0-r0 | 68.11.0-r0 |
| Alpine:v3.12 | firefox | before 79.0-r0 | 79.0-r0 |
| Alpine:v3.12 | firefox-esr | before 78.1.0-r0 | 78.1.0-r0 |
| Alpine:v3.12 | mozjs68 | before 68.11.0-r0 | 68.11.0-r0 |
| Alpine:v3.21 | librewolf | before 79.0-r0 | 79.0-r0 |
| Debian:10 | firefox-esr | before 68.11.0esr-1~deb10u1 | 68.11.0esr-1~deb10u1 |
| Debian:10 | thunderbird | before 1:68.11.0-1~deb10u1 | 1:68.11.0-1~deb10u1 |
| Debian:12 | firefox-esr | before 68.11.0esr-1 | 68.11.0esr-1 |
| Debian:12 | thunderbird | before 1:68.11.0-1 | 1:68.11.0-1 |
| Debian:9 | firefox-esr | before 68.11.0esr-1~deb9u1 | 68.11.0esr-1~deb9u1 |
| Debian:9 | thunderbird | before 1:68.11.0-1~deb9u1 | 1:68.11.0-1~deb9u1 |
| openSUSE:Leap 15.1 | MozillaFirefox | before 78.1.0-lp151.2.61.1 | 78.1.0-lp151.2.61.1 |
| openSUSE:Leap 15.1 | MozillaThunderbird | before 68.11.0-lp151.2.47.1 | 68.11.0-lp151.2.47.1 |
| openSUSE:Leap 15.2 | MozillaFirefox | before 78.1.0-lp152.2.12.1 | 78.1.0-lp152.2.12.1 |
| openSUSE:Leap 15.2 | MozillaFirefox | before 78.1.0-lp152.2.15.1 | 78.1.0-lp152.2.15.1 |
| openSUSE:Leap 15.2 | MozillaThunderbird | before 68.11.0-lp152.2.7.1 | 68.11.0-lp152.2.7.1 |
| openSUSE:Leap 15.2 | pipewire | before 0.3.6-lp152.2.3.1 | 0.3.6-lp152.2.3.1 |
| Red Hat:enterprise_linux:6::client | firefox | before 0:68.11.0-1.el6_10 | 0:68.11.0-1.el6_10 |
| Red Hat:enterprise_linux:6::client | firefox-debuginfo | before 0:68.11.0-1.el6_10 | 0:68.11.0-1.el6_10 |
| Red Hat:enterprise_linux:6::client | thunderbird | before 0:68.11.0-1.el6_10 | 0:68.11.0-1.el6_10 |
| Red Hat:enterprise_linux:6::client | thunderbird-debuginfo | before 0:68.11.0-1.el6_10 | 0:68.11.0-1.el6_10 |
| Red Hat:enterprise_linux:7::client | firefox | before 0:68.11.0-1.el7_8 | 0:68.11.0-1.el7_8 |
| Red Hat:enterprise_linux:7::client | firefox-debuginfo | before 0:68.11.0-1.el7_8 | 0:68.11.0-1.el7_8 |
| Red Hat:enterprise_linux:7::client | thunderbird | before 0:68.11.0-1.el7_8 | 0:68.11.0-1.el7_8 |
+26
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2010-3765Mozilla 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…KEV94Now
- CVE-2019-11708Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the…KEV87Now
- CVE-2015-4495The 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…KEV86Now
Published before and after this one in the same product
- ← EarlierCVE-2020-15657Aug 10, 2020 · Firefox could be made to load attacker-supplied DLL files from the installation directory.31Monitor
- ← EarlierCVE-2020-15658Aug 10, 2020 · The code for downloading files did not properly take care of special characters, which led to an attacker being able to cut off the file…26Monitor
- Later →CVE-2020-15663Oct 1, 2020 · If Firefox is installed to a user-writable directory, the Mozilla Maintenance Service would execute updater.exe from the install location…36Monitor
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 |
|---|---|---|
| alpine:firefox | 79.0-r0 · Alpine:v3.12 | Package registry (OSV) |
| alpine:firefox-esr | 68.11.0-r0 · Alpine:v3.11 | Package registry (OSV) |
| alpine:librewolf | 79.0-r0 · Alpine:v3.21 | Package registry (OSV) |
| alpine:mozjs68 | 68.11.0-r0 · Alpine:v3.12 | Package registry (OSV) |
| debian:firefox-esr | 68.11.0esr-1 · Debian:12 | Package registry (OSV) |
| debian:thunderbird | 1:68.11.0-1 · Debian:12 | Package registry (OSV) |
| opensuse:MozillaFirefox | 78.1.0-lp151.2.61.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| opensuse:MozillaThunderbird | 68.11.0-lp151.2.47.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| opensuse:pipewire | 0.3.6-lp152.2.3.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:firefox | 0:68.11.0-1.el8_0 · Red Hat:rhel_e4s:8.0::appstream | Package registry (OSV) |
| red hat:firefox-debuginfo | 0:68.11.0-1.el8_0 · Red Hat:rhel_e4s:8.0::appstream | Package registry (OSV) |
| red hat:firefox-debugsource | 0:68.11.0-1.el8_0 · Red Hat:rhel_e4s:8.0::appstream | Package registry (OSV) |
| red hat:thunderbird | 0:68.11.0-1.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:thunderbird-debuginfo | 0:68.11.0-1.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:thunderbird-debugsource | 0:68.11.0-1.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| suse:MozillaFirefox | 78.1.0-78.87.1 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:MozillaFirefox-branding-SLE | 78-9.2.4 · SUSE:Linux Enterprise Module for Desktop Applications 15 SP2 | Package registry (OSV) |
| suse:MozillaThunderbird | 68.11.0-3.91.1 · SUSE:Linux Enterprise Workstation Extension 15 SP1 | Package registry (OSV) |
| suse:pipewire | 0.3.6-3.3.2 · SUSE:Linux Enterprise Module for Desktop Applications 15 SP2 | 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.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-20-573 · Aug 7, 2020(Thunderbird Zafiyeti)
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Anyone who can reach it over the internet 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
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log (1)
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (9 more)Show less
- lists.opensuse.org/opensuse-security-announce/2020-08/msg00025.html
- lists.opensuse.org/opensuse-security-announce/2020-08/msg00032.html
- bugzilla.mozilla.org/buglist.cgi?bug_id=1550133%2C1633880%2C1643613%2C1644839%2C1645835%2C1646006%2C1646787%2C1649347%2C1650811%2C1651678
- usn.ubuntu.com/4443-1/
- www.mozilla.org/security/advisories/mfsa2020-30/
- www.mozilla.org/security/advisories/mfsa2020-31/
- www.mozilla.org/security/advisories/mfsa2020-32/
- www.mozilla.org/security/advisories/mfsa2020-33/
- www.mozilla.org/security/advisories/mfsa2020-35/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.