Vulnerability · Published Jun 24, 2021 · Assigned by mozilla
CVE-2021-23995
High 8.8
In plain English
A high-severity security flaw in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 68% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)8.8High
Exploit odds (30 days)1.2%top 32.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.21 | firefox | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.22 | firefox | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.23 | firefox | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.20 | firefox-esr | 78.10.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.21 | firefox-esr | 78.10.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.22 | firefox-esr | 78.10.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.23 | firefox-esr | 78.10.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.21 | librewolf | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.22 | librewolf | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.23 | librewolf | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.24 | librewolf | 88.0-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.20 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.21 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.22 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-23995 |
| Alpine:v3.23 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-23995 |
| Debian:12 | firefox-esr | 78.10.0esr-1 | DEBIAN-CVE-2021-23995 |
| Debian:13 | firefox-esr | 78.10.0esr-1 | DEBIAN-CVE-2021-23995 |
| Debian:14 | firefox-esr | 78.10.0esr-1 | DEBIAN-CVE-2021-23995 |
| Debian:12 | thunderbird | 1:78.10.0-1 | DEBIAN-CVE-2021-23995 |
| Debian:13 | thunderbird | 1:78.10.0-1 | DEBIAN-CVE-2021-23995 |
| Debian:14 | thunderbird | 1:78.10.0-1 | DEBIAN-CVE-2021-23995 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2021-23995 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox ESR | unspecified – before 78.10 |
| Mozilla | Thunderbird | unspecified – before 78.10 |
| Mozilla | Firefox | unspecified – before 88 |
References
- https://www.mozilla.org/security/advisories/mfsa2021-14/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-16/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-15/ x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1699835 x_refsource_MISC