CVE-2020-12387: mozilla firefox Race Condition
CVSS: 8.1v3.1HighModified
AliasesUBUNTU-CVE-2020-12387DEBIAN-CVE-2020-12387
Published 26-05-2020Last modified 04-08-2024
Vulnerability summary
CVE-2020-12387 is a high (CVSS 8.1) Race Condition vulnerability in mozilla firefox. EPSS estimates a 1.44% chance of exploitation in the next 30 days, higher than 72.7% of scored vulnerabilities.
CVSS score
8.1/10
010
High · v3.1 (NVD)EPSS score
1.44%
0%100%
Low · +0.03 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 27 · Related 11DLA-2205-1DLA-2206-1DSA-4678-1DSA-4683-1MGASA-2020-0208MGASA-2020-0209OPENSUSE-SU-2020:0621-1OPENSUSE-SU-2020:0643-1OPENSUSE-SU-2024:10600-1OPENSUSE-SU-2024:10601-1OPENSUSE-SU-2024:14572-1RHSA-2020:2031RHSA-2020:2032RHSA-2020:2033RHSA-2020:2036RHSA-2020:2037RHSA-2020:2046RHSA-2020:2047RHSA-2020:2048RHSA-2020:2049RHSA-2020:2050SUSE-SU-2020:1209-1SUSE-SU-2020:1218-1SUSE-SU-2020:1225-1SUSE-SU-2020:14359-1USN-4353-1USN-4373-1
Timeline
- 26-05-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
A race condition when running shutdown code for Web Worker led to a use-after-free vulnerability. This resulted in a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.
CVSS metrics
4 scores · 3 sources · 2 versionsHigh 8.1Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Medium 6.8Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
1.44%
Chance of exploitation in the next 30 days
Percentile
73%
Versus all other CVEs
30-day change
+0.03 pp
From 1.40% on 20-09-2026
20-09-202620-10-2026
EPSS score1.44%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
- 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.
Affected systems
Ubuntu5 products
- firefox< 76.0+build2-0ubuntu0.16.04.1 | < 76.0+build2-0ubuntu0.18.04.1 | < 76.0+build2-0ubuntu0.20.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- thunderbird< 1:68.8.0+build2-0ubuntu0.16.04.2 | < 1:68.8.0+build2-0ubuntu0.18.04.2 | < 1:68.8.0+build2-0ubuntu0.20.04.2
Mozilla3 products
- firefox≥ unspecified, < 76 | < 76.0
- firefox_esr≥ unspecified, < 68.8 | < 68.8.0
- thunderbird≥ unspecified, < 68.8.0 | < 68.8.0
Debian2 products
- firefox-esr< 68.8.0esr-1
- thunderbird< 1:68.8.0-1
3 vendors · 10 products
