Vulnerability · Published Dec 9, 2020 · Assigned by mozilla
CVE-2020-26951
Medium 6.1
In plain English
A medium-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 1.1% (higher than 64% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)6.1Medium
Exploit odds (30 days)1.1%top 35.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. 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-esr | 78.5.0-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.21 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.22 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.23 | firefox-esr | 78.5.0-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.20 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.21 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.22 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26951 |
| Alpine:v3.23 | thunderbird | 78.5.1-r0 | ALPINE-CVE-2020-26951 |
| Debian:12 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26951 |
| Debian:13 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26951 |
| Debian:14 | firefox-esr | 78.5.0esr-1 | DEBIAN-CVE-2020-26951 |
| Debian:12 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26951 |
| Debian:13 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26951 |
| Debian:14 | thunderbird | 1:78.5.0-1 | DEBIAN-CVE-2020-26951 |
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=1667113 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