CVE-2026-74984: mozilla firefox Race Condition
CVSS: 6.8v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-74984
Published 18-08-2026Last modified 20-08-2026
Vulnerability summary
CVE-2026-74984 is a medium (CVSS 6.8) Race Condition vulnerability in mozilla firefox. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19% of scored vulnerabilities.
CVSS score
6.8/10
010
Medium · v3.1 (CVE.org)EPSS score
0.28%
0%100%
Low · +0.09 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 13 · Related 11Timeline
- 18-08-2026PublishedVulnerability first disclosed.
- 20-08-2026Last modifiedVulnerability information updated.
Description
Race condition in the JavaScript Engine component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
CVSS metrics
3 scores · 3 sources · 1 versionMedium 6.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- NVDNIST6.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
19%
Versus all other CVEs
30-day change
+0.09 pp
From 0.19% on 19-09-2026
19-09-202619-10-2026
EPSS score0.28%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu8 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
Mozilla2 products
- firefox< 153.1.0
- thunderbird< 153.1.0
2 vendors · 10 products
References
8 links- bugzilla.mozilla.org/show_bug.cgi?id=2053670Permissions Required
- www.mozilla.org/security/advisories/mfsa2026-74/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-77/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-78/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-80/Vendor Advisory