Vulnerability · Published Dec 8, 2021 · Assigned by mozilla
CVE-2021-43534
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 1.2% (higher than 69% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)8.8High
Exploit odds (30 days)1.2%top 30.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
Mozilla developers and community members reported memory safety bugs present in Firefox 93 and Firefox ESR 91.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-43534 |
| Alpine:v3.21 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-43534 |
| Alpine:v3.22 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-43534 |
| Alpine:v3.23 | thunderbird | 91.3.2-r0 | ALPINE-CVE-2021-43534 |
| Debian:12 | firefox-esr | 91.3.0esr-1 | DEBIAN-CVE-2021-43534 |
| Debian:13 | firefox-esr | 91.3.0esr-1 | DEBIAN-CVE-2021-43534 |
| Debian:14 | firefox-esr | 91.3.0esr-1 | DEBIAN-CVE-2021-43534 |
| Debian:12 | thunderbird | 1:91.3.0-1 | DEBIAN-CVE-2021-43534 |
| Debian:13 | thunderbird | 1:91.3.0-1 | DEBIAN-CVE-2021-43534 |
| Debian:14 | thunderbird | 1:91.3.0-1 | DEBIAN-CVE-2021-43534 |
| Rocky Linux:8 | firefox | 0:91.3.0-1.el8 | RLSA-2021:4123 |
| Rocky Linux:8 | thunderbird | 0:91.3.0-2.el8 | RLSA-2021:4130 |
| Rocky Linux:8 | thunderbird | 0:91.3.0-2.el8_4 | RLSA-2021:4130 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | unspecified – before 94 |
| Mozilla | Thunderbird | unspecified – before 91.3 |
| Mozilla | Firefox ESR | unspecified – before 91.3 |
References
- https://www.mozilla.org/security/advisories/mfsa2021-49/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-50/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2021-48/ x_refsource_MISC
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1606864%2C1712671%2C1730048%2C1735152 x_refsource_MISC
- DSA-5026 vendor-advisory, x_refsource_DEBIAN
- [debian-lts-announce] 20211229 [SECURITY] [DLA 2863-1] firefox-esr security update mailing-list, x_refsource_MLIST
- DSA-5034 vendor-advisory, x_refsource_DEBIAN
- [debian-lts-announce] 20220104 [SECURITY] [DLA 2874-1] thunderbird security update mailing-list, x_refsource_MLIST