Vulnerability · Published Feb 26, 2021 · Assigned by mozilla
CVE-2021-23953
Medium 4.3
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 65% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)4.3Medium
Exploit odds (30 days)1.1%top 35.4% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox-esr | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.21 | firefox-esr | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.22 | firefox-esr | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.23 | firefox-esr | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.20 | thunderbird | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.21 | thunderbird | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.22 | thunderbird | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Alpine:v3.23 | thunderbird | 78.7.0-r0 | ALPINE-CVE-2021-23953 |
| Debian:12 | firefox-esr | 78.7.0esr-1 | DEBIAN-CVE-2021-23953 |
| Debian:13 | firefox-esr | 78.7.0esr-1 | DEBIAN-CVE-2021-23953 |
| Debian:14 | firefox-esr | 78.7.0esr-1 | DEBIAN-CVE-2021-23953 |
| Debian:12 | thunderbird | 1:78.7.0-1 | DEBIAN-CVE-2021-23953 |
| Debian:13 | thunderbird | 1:78.7.0-1 | DEBIAN-CVE-2021-23953 |
| Debian:14 | thunderbird | 1:78.7.0-1 | DEBIAN-CVE-2021-23953 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2021-23953 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 85 |
| Mozilla | Thunderbird | < 78.7 |
| Mozilla | Firefox ESR | < 78.7 |
References
- https://www.mozilla.org/security/advisories/mfsa2021-03/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-04/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-05/ x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1683940 x_refsource_MISC