CVE-2026-8952: mozilla firefox Improper Privilege Management
CVSS: 8.8v3.1HighModified
AliasesUBUNTU-CVE-2026-8952CGA-9wcc-wm6j-p639CGA-cv33-6gmq-9pwm
Published 19-05-2026Last modified 20-05-2026
Vulnerability summary
CVE-2026-8952 is a high (CVSS 8.8) Improper Privilege Management vulnerability in mozilla firefox. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33.2% of scored vulnerabilities.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.40%
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 2 · Related 3Timeline
- 19-05-2026PublishedVulnerability first disclosed.
- 20-05-2026Last modifiedVulnerability information updated.
Description
Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
CVSS metrics
3 scores · 3 sources · 1 versionHigh 8.8Preferred score · CVE.org (CNA)
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
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.40%
Chance of exploitation in the next 30 days
Percentile
33%
Versus all other CVEs
30-day change
+0.03 pp
From 0.37% on 21-09-2026
21-09-202621-10-2026
EPSS score0.40%
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< 151.0.0
- thunderbird< 151.0.0
Chainguard1 product
- firefox< 151-r0
Wolfi1 product
- firefox< 151-r0
4 vendors · 12 products