CVE-2016-5254

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

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 v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
87%
KEV
Not listed

Published

August 5, 2016

Last Modified

June 17, 2026

Advisory Details (5)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

1266963 - (CVE-2016-5254) Heap-use-after-free in nsXULPopupManager::KeyDown

https://bugzilla.mozilla.org/show_bug.cgi?id=1266963
generic

CVE-2016-5254 - PSIRT.COM

http://www.securityfocus.com/bid/92261
generic

[SECURITY] [DSA 3640-1] firefox-esr security update

http://www.debian.org/security/2016/dsa-3640
generic
http://rhn.redhat.com/errata/RHSA-2016-1551.html
generic
http://www.securitytracker.com/id/1036508

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-testsuite (48.0+build2-0ubuntu0.16.04.1) @ xenial2026-05-20ubuntu
redhatfirefox-0:45.3.0-1.el7_22016-08-03redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
firefox-esr—45.3.0esr-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
firefox-esr—45.3.0esr-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
firefox-esr—45.3.0esr-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
firefox-esr—45.3.0esr-1—
Debian:7(1)
PackageVulnerable rangeFixed inDependents
firefox-esr45.0.1esr-1 ... 45.2.0esr-1~deb8u1 (9 versions)45.3.0esr-1~deb7u1—
Debian:8(1)
PackageVulnerable rangeFixed inDependents
firefox-esr45.0.1esr-1 ... 45.3.0esr-1~deb7u1 (10 versions)45.3.0esr-1~deb8u1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 6× in last 7d / 19× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 162 total refreshes for this CVE.

  1. 2026-09-19 15:35 UTCEPSS rescore
  2. 2026-09-18 19:22 UTCEPSS rescore
  3. 2026-09-17 19:21 UTCEPSS rescore
  4. 2026-09-15 03:05 UTCEPSS rescore
  5. 2026-09-14 22:44 UTCOSV refresh
  6. 2026-09-13 16:41 UTCEPSS rescore
  7. 2026-09-12 14:55 UTCEPSS rescore
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  15. 2026-08-26 22:03 UTCOSV refresh
  16. 2026-08-26 14:41 UTCEPSS rescore
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  1. 2026-08-12 13:46 UTCEPSS rescore
  2. 2026-08-11 13:36 UTCEPSS rescore
  3. 2026-08-10 12:10 UTCOSV refresh
  4. 2026-08-09 13:42 UTCEPSS rescore
  5. 2026-08-08 16:32 UTCEPSS rescore
  6. 2026-08-06 13:42 UTCEPSS rescore
  7. 2026-08-05 19:12 UTCEPSS rescore
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  9. 2026-08-04 10:32 UTCEPSS rescore
  10. 2026-08-02 02:22 UTCEPSS rescore
  11. 2026-08-01 04:11 UTCEPSS rescore
  12. 2026-07-30 16:23 UTCEPSS rescore
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  14. 2026-07-28 15:31 UTCEPSS rescore
  15. 2026-07-26 14:50 UTCEPSS rescore
  16. 2026-07-25 14:13 UTCEPSS rescore
  17. 2026-07-25 12:41 UTCOSV refresh
  18. 2026-07-23 14:14 UTCEPSS rescore
  19. 2026-07-23 01:23 UTCEG score recompute
  20. 2026-07-22 22:02 UTCEG score recompute
  21. 2026-07-22 14:04 UTCEPSS rescore
  22. 2026-07-21 15:21 UTCEPSS rescore
  23. 2026-07-21 15:21 UTCEPSS rescore
  24. 2026-07-20 17:03 UTCEPSS rescore
  25. 2026-07-19 14:27 UTCEPSS rescore
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  27. 2026-07-19 02:26 UTCEPSS rescore
  28. 2026-07-18 10:00 UTCEPSS rescore
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  30. 2026-07-16 16:59 UTCEPSS rescore
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  36. 2026-07-13 22:26 UTCEPSS rescore
  37. 2026-07-12 05:43 UTCEPSS rescore
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  40. 2026-07-09 19:05 UTCEPSS rescore
  41. 2026-07-08 15:10 UTCEPSS rescore
  42. 2026-07-08 07:27 UTCOSV refresh
  43. 2026-07-07 13:42 UTCEPSS rescore
  44. 2026-07-06 16:24 UTCEPSS rescore
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  46. 2026-07-06 02:20 UTCEPSS rescore
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  48. 2026-07-05 02:27 UTCEPSS rescore
  49. 2026-07-04 06:28 UTCEPSS rescore
  50. 2026-07-01 15:02 UTCEPSS rescore
  51. 2026-06-30 23:19 UTCEPSS rescore
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  65. 2026-06-21 01:57 UTCEPSS rescore
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  67. 2026-06-19 19:25 UTCOSV refresh
  68. 2026-06-19 19:23 UTCEPSS rescore
  69. 2026-06-19 19:23 UTCEPSS rescore
  70. 2026-06-18 17:50 UTCEPSS rescore
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  75. 2026-06-15 17:45 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2016-5254?
CVE-2016-5254 is a critical vulnerability published on August 5, 2016. 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…
When was CVE-2016-5254 disclosed?
CVE-2016-5254 was first published in the National Vulnerability Database on August 5, 2016, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-5254 actively exploited?
CVE-2016-5254 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 13.4% of all scored CVEs.
What is the CVSS score of CVE-2016-5254?
CVE-2016-5254 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-5254?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-5254, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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