Vulnerability · Published Dec 9, 2020 · Assigned by mozilla
CVE-2020-26959
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 1.3% (higher than 71% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)8.8High
Exploit odds (30 days)1.3%top 29.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.21 | firefox | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.22 | firefox | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.23 | firefox | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.20 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.21 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.22 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.23 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.21 | librewolf | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.22 | librewolf | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.23 | librewolf | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.24 | librewolf | 83.0-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.20 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.21 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.22 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26959 |
| Alpine:v3.23 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26959 |
| Debian:12 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26959 |
| Debian:13 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26959 |
| Debian:14 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26959 |
| Debian:12 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26959 |
| Debian:13 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26959 |
| Debian:14 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26959 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 83 |
| Mozilla | Firefox ESR | < 78.5 |
| Mozilla | Thunderbird | < 78.5 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1669466 x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2020-50/ x_refsource_CONFIRM
- https://www.mozilla.org/security/advisories/mfsa2020-52/ x_refsource_CONFIRM
- https://www.mozilla.org/security/advisories/mfsa2020-51/ x_refsource_CONFIRM