CVE-2016-5254: mozilla firefox Use After Free
Vulnerability summary
CVE-2016-5254 is a critical (CVSS 9.8) Use After Free vulnerability in mozilla firefox. EPSS estimates a 2.95% chance of exploitation in the next 30 days, higher than 87.1% of scored vulnerabilities.
Severe, CVSS 9.8 (NVD); no exploitation reported by the 5 checked sources; EPSS 3% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 13 · Related 9Timeline
- 05-08-2016PublishedVulnerability first disclosed.
- 06-08-2024Last modifiedVulnerability information updated.
Description
Use-after-free vulnerability in the nsXULPopupManager::KeyDown function in Mozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allows attackers to execute arbitrary code or cause a denial of service (heap memory corruption and application crash) by leveraging keyboard access to use the Alt key during selection of top-level menu items.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
2.95%
Chance of exploitation in the next 30 days
Percentile
87%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.95% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- firefox-esr< 45.3.0esr-1
Mozilla1 product
- firefox≤ 47.0.1 | 45.1.0 | 45.1.1 | 45.2.0 | 45.3.0
Oracle1 product
- linuxEOL5.0 | 6 | 7
Ubuntu1 product
- firefox< 48.0+build2-0ubuntu0.14.04.1 | < 48.0+build2-0ubuntu0.16.04.1
4 vendors · 4 products
References
16 links
- bugzilla.mozilla.org/show_bug.cgi?id=1266963X Refsource CONFIRMIssue TrackingPermissions RequiredREPORT
- www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.htmlX Refsource CONFIRMThird Party Advisory