Vulnerability · Published Dec 9, 2020 · Assigned by mozilla
CVE-2020-26950
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 42.3% (higher than 99% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit. Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)8.8High
Exploit odds (30 days)42.3%top 1.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling1Metasploit
Official description
In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.21 | firefox | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.22 | firefox | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.23 | firefox | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.20 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.21 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.22 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.23 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.21 | librewolf | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.22 | librewolf | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.23 | librewolf | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.24 | librewolf | 82.0.3-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.20 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.21 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.22 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26950 |
| Alpine:v3.23 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26950 |
| Debian:12 | firefox-esr | 78.4.1esr-1 | DEBIAN-CVE-2020-26950 |
| Debian:13 | firefox-esr | 78.4.1esr-1 | DEBIAN-CVE-2020-26950 |
| Debian:14 | firefox-esr | 78.4.1esr-1 | DEBIAN-CVE-2020-26950 |
| Debian:12 | thunderbird | 1:78.4.2-1 | DEBIAN-CVE-2020-26950 |
| Debian:13 | thunderbird | 1:78.4.2-1 | DEBIAN-CVE-2020-26950 |
| Debian:14 | thunderbird | 1:78.4.2-1 | DEBIAN-CVE-2020-26950 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 82.0.3 |
| Mozilla | Firefox ESR | < 78.4.1 |
| Mozilla | Thunderbird | < 78.4.2 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1675905 x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2020-49/ x_refsource_CONFIRM
- http://packetstormsecurity.com/files/166175/Firefox-MCallGetProperty-Write-Side-Effects-Use-After-Free.html x_refsource_MISC