Integer underflow in the nsHtml5TreeBuilder class in the HTML5 string parser in Mozilla Firefox before 45.0 and Firefox ESR 38.x before 38.7 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) by leveraging mishandling of end tags, as demonstrated by incorrect SVG processing, aka ZDI-CAN-3545.
Conclusion & alert: CVE-2016-1960 is rated High Exploit Risk (84.4/100): CVSS High severity, with high exploitation likelihood (EPSS 86.45%, 99th percentile). Core evidence: 2 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| 44294 | exploit_db | edb | 2018-03-16 | Exploit-DB ↗ |
| 42484 | exploit_db | edb | 2017-08-18 | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-05 | 87.06% | 86.45% | -0.60% |
| 2 | 2026-03-02 | 86.70% | 87.06% | +0.36% |
| 3 | 2026-02-18 | — | 86.70% | — |
Full EPSS history (14 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.8 | 3.0 | HIGH |
|
2.8 | 5.9 | [email protected] |
| 6.8 | 2.0 | MEDIUM |
|
8.6 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2016-1960 not yet assigned priority: Debian including 2 source packages (firefox, firefox-esr), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. | https://security-tracker.debian.org/tracker/CVE-2016-1960 |
gentoo
|
normal | CVE-2016-1960: 1 GLSA(s) (201605-06), 6 atom(s) (dev-libs/nspr, dev-libs/nss, mail-client/thunderbird, mail-client/thunderbird-bin, www-client/firefox, www-client/firefox-bin); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-1960 |
redhat
|
critical | — | https://access.redhat.com/security/cve/CVE-2016-1960 |
suse
|
high | CVE-2016-1960 severity important: SUSE including 151 source package names (MozillaFirefox-102.11.0-150200.152.87.1, MozillaFirefox-115.10.0-150200.152.134.1, …), 389 product×package rows across 71 product lines (Image SLES12-SP5-Azure-BYOS, Image SLES12-SP5-Azure-Basic-On-Demand, … (71 product lines)): Fixed 389. | https://www.suse.com/security/cve/CVE-2016-1960/ |
ubuntu
|
medium | CVE-2016-1960 medium priority: Ubuntu including 2 source packages (firefox, thunderbird), 10 status rows across 5 suites (precise, trusty, upstream, wily, xenial): released 9, not-affected 1. | https://ubuntu.com/security/CVE-2016-1960 |
: <a href="http://cwe.mitre.org/data/definitions/416.html">CWE-416: Use After Free</a>
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| oracle | linux | 5.0 | cpe:2.3:o:oracle:linux:5.0:*:*:*:*:*:*:* |
| oracle | linux | 6 | cpe:2.3:o:oracle:linux:6:*:*:*:*:*:*:* |
| oracle | linux | 7 | cpe:2.3:o:oracle:linux:7:*:*:*:*:*:*:* |
| mozilla | firefox | <= 44.0.2 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | firefox | 38.0 | cpe:2.3:a:mozilla:firefox:38.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.0.1 | cpe:2.3:a:mozilla:firefox:38.0.1:*:*:*:*:*:*:* |
| mozilla | firefox | 38.0.5 | cpe:2.3:a:mozilla:firefox:38.0.5:*:*:*:*:*:*:* |
| mozilla | firefox | 38.1.0 | cpe:2.3:a:mozilla:firefox:38.1.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.1.1 | cpe:2.3:a:mozilla:firefox:38.1.1:*:*:*:*:*:*:* |
| mozilla | firefox | 38.2.0 | cpe:2.3:a:mozilla:firefox:38.2.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.2.1 | cpe:2.3:a:mozilla:firefox:38.2.1:*:*:*:*:*:*:* |
| mozilla | firefox | 38.3.0 | cpe:2.3:a:mozilla:firefox:38.3.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.4.0 | cpe:2.3:a:mozilla:firefox:38.4.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.5.0 | cpe:2.3:a:mozilla:firefox:38.5.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.5.1 | cpe:2.3:a:mozilla:firefox:38.5.1:*:*:*:*:*:*:* |
| mozilla | firefox | 38.6.0 | cpe:2.3:a:mozilla:firefox:38.6.0:*:*:*:*:*:*:* |
| mozilla | firefox | 38.6.1 | cpe:2.3:a:mozilla:firefox:38.6.1:*:*:*:*:*:*:* |
| mozilla | thunderbird | <= 38.6.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| opensuse | leap | 42.1 | cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:* |
| opensuse | opensuse | 13.1 | cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:* |
| opensuse | opensuse | 13.2 | cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:* |
| suse | linux_enterprise | 12.0 | cpe:2.3:o:suse:linux_enterprise:12.0:*:*:*:*:*:*:* |