CVE-2021-29970: mozilla firefox Use After Free
CVSS: 8.8v3.1HighModified
AliasesUBUNTU-CVE-2021-29970DEBIAN-CVE-2021-29970
Published 05-08-2021Last modified 03-08-2024
Vulnerability summary
CVE-2021-29970 is a high (CVSS 8.8) Use After Free vulnerability in mozilla firefox. EPSS estimates a 1.43% chance of exploitation in the next 30 days, higher than 72.6% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
8.8/10
010
High · v3.1 (NVD)EPSS score
1.43%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Advisory lineage
Upstream 0 · Downstream 28 · Related 14DLA-2709-1DLA-2711-1DSA-4939-1DSA-4940-1MGASA-2021-0354MGASA-2021-0355OPENSUSE-SU-2021:1066-1OPENSUSE-SU-2021:1091-1OPENSUSE-SU-2021:2393-1OPENSUSE-SU-2021:2458-1OPENSUSE-SU-2024:10600-1OPENSUSE-SU-2024:10601-1OPENSUSE-SU-2024:14572-1RHSA-2021:2740RHSA-2021:2741RHSA-2021:2742RHSA-2021:2743RHSA-2021:2881RHSA-2021:2882RHSA-2021:2883RHSA-2021:2914SUSE-SU-2021:14766-1SUSE-SU-2021:2389-1SUSE-SU-2021:2393-1SUSE-SU-2021:2458-1SUSE-SU-2021:2478-1USN-5011-1USN-5058-1
Timeline
- 05-08-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
A malicious webpage could have triggered a use-after-free, memory corruption, and a potentially exploitable crash. *This bug could only be triggered when accessibility was enabled.*. This vulnerability affects Thunderbird < 78.12, Firefox ESR < 78.12, and Firefox < 90.
CVSS metrics
4 scores · 3 sources · 2 versionsHigh 8.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Medium 5.1Preferred score · NVD (NIST)
AV:N/AC:H/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
1.43%
Chance of exploitation in the next 30 days
Percentile
73%
Versus all other CVEs
30-day change
0.00 pp
From 1.43% on 20-09-2026
20-09-202620-10-2026
EPSS score1.43%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (bugzilla.mozilla.org)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Ubuntu6 products
- firefox< 90.0+build1-0ubuntu0.18.04.1 | < 90.0+build1-0ubuntu0.20.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- mozjs78All versions (No fix recorded)
Mozilla3 products
- firefox≥ unspecified, < 90 | < 90.0
- firefox_esr≥ unspecified, < 78.12 | < 78.12
- thunderbird≥ unspecified, < 78.12 | < 78.12
Debian2 products
- firefox-esr< 78.12.0esr-1
- thunderbird< 1:78.12.0-1
3 vendors · 11 products
