Vulnerability · Published Dec 22, 2022 · Assigned by mozilla
CVE-2021-4140
Critical 9.8
In plain English
A critical-severity security flaw in Firefox from Mozilla. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 73% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)1.4%top 27.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | firefox | 91.5.0-1.el8_5.alma | ALSA-2022:0130 |
| AlmaLinux:8 | thunderbird | 91.5.0-1.el8_5.alma | ALSA-2022:0129 |
| AlmaLinux:8 | thunderbird | 91.5.0-1.el8_5.alma.plus | ALSA-2022:0129 |
| Alpine:v3.20 | firefox | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.21 | firefox | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.22 | firefox | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.23 | firefox | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.20 | firefox-esr | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.21 | firefox-esr | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.22 | firefox-esr | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.23 | firefox-esr | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.21 | librewolf | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.22 | librewolf | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.23 | librewolf | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.24 | librewolf | 97.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.20 | thunderbird | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.21 | thunderbird | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.22 | thunderbird | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Alpine:v3.23 | thunderbird | 91.5.0-r0 | ALPINE-CVE-2021-4140 |
| Debian:12 | firefox-esr | 91.5.0esr-1 | DEBIAN-CVE-2021-4140 |
| Debian:13 | firefox-esr | 91.5.0esr-1 | DEBIAN-CVE-2021-4140 |
| Debian:14 | firefox-esr | 91.5.0esr-1 | DEBIAN-CVE-2021-4140 |
| Debian:12 | thunderbird | 1:91.5.0-1 | DEBIAN-CVE-2021-4140 |
| Debian:13 | thunderbird | 1:91.5.0-1 | DEBIAN-CVE-2021-4140 |
| Debian:14 | thunderbird | 1:91.5.0-1 | DEBIAN-CVE-2021-4140 |
| Rocky Linux:8 | firefox | 0:91.5.0-1.el8_5 | RLSA-2022:0130 |
| Rocky Linux:8 | thunderbird | 0:91.5.0-1.el8_5 | RLSA-2022:0129 |
| Ubuntu:22.04:LTS | firefox | 96.0+build2-0ubuntu1 | UBUNTU-CVE-2021-4140 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2021-4140 |
| Ubuntu:22.04:LTS | thunderbird | 1:91.5.0+build1-0ubuntu1 | UBUNTU-CVE-2021-4140 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox ESR | unspecified – before 91.5 |
| Mozilla | Firefox | unspecified – before 96 |
| Mozilla | Thunderbird | unspecified – before 91.5 |
Weakness: CWE-91 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H