CVE-2019-9821: mozilla firefox Race Condition
CVSS: 8.1v3.0HighModified
AliasesUBUNTU-CVE-2019-9821
Published 23-07-2019Last modified 04-08-2024
Vulnerability summary
CVE-2019-9821 is a high (CVSS 8.1) Race Condition vulnerability in mozilla firefox. EPSS estimates a 0.85% chance of exploitation in the next 30 days, higher than 57.3% of scored vulnerabilities.
CVSS score
8.1/10
010
High · v3.0 (NVD)EPSS score
0.85%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 4 · Related 4Timeline
- 23-07-2019PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
A use-after-free vulnerability can occur in AssertWorkerThread due to a race condition with shared workers. This results in a potentially exploitable crash. This vulnerability affects Firefox < 67.
CVSS metrics
3 scores · 2 sources · 2 versionsHigh 8.1Preferred score · NVD (NIST)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 2 agree
- OSV · UbuntuEcosystem advisory · calculated8.1HighCVSS:3.0/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
0.85%
Chance of exploitation in the next 30 days
Percentile
57%
Versus all other CVEs
30-day change
0.00 pp
From 0.85% on 19-09-2026
19-09-202619-10-2026
EPSS score0.85%
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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
Ubuntu3 products
- firefox< 67.0+build2-0ubuntu0.16.04.1 | < 67.0+build2-0ubuntu0.18.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
Mozilla1 product
- firefox≥ unspecified, < 67 | < 67.0
2 vendors · 4 products