CVE Intelligence
CISA KEV Critical Memory corruption exploit reference

CVE-2020-15999 — Google Chrome FreeType Heap Buffer Overflow Vulnerability

Heap buffer overflow in Freetype in Google Chrome prior to 86.0.4240.111 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Published Nov 3, 2020 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Chrome

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Nov 3, 2021 Proofs of concept on GitHub · 3
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Public exploit/PoC (github)+6
  • EPSS 63.9% (30-day exploitation probability)+15
  • Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Nov 3, 2021
EPSS FIRST
63.89%
ahead of 99% of scored CVEs · Oct 16, 2026
Affects
Debian
Debian Linux and 9 more
CVSS base
9.6
Critical · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Nuget CefSharp.Common: fixed in version 85.3.130 — github.com (GitHub Security Advisories)
  • Nuget CefSharp.WinForms: fixed in version 85.3.130 — github.com (GitHub Security Advisories)
  • Nuget CefSharp.Wpf: fixed in version 85.3.130 — github.com (GitHub Security Advisories)
  • Nuget CefSharp.Wpf.HwndHost: fixed in version 85.3.130 — github.com (GitHub Security Advisories)

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Nov 17, 2021 — passed 1795 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Fedoraproject Fedora, Freetype Freetype…).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  4. Apply the fixed version or the patch documented under Remediation.
  5. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  6. EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
  7. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Debian Debian Linux version 10.0 Vulnerable NIST National Vulnerability Database
Fedoraproject Fedora version 31 Vulnerable NIST National Vulnerability Database
Freetype Freetype ≥ 2.6.0 and < 2.10.4 Vulnerable NIST National Vulnerability Database
Google Chrome < 86.0.4240.111 Vulnerable NIST National Vulnerability Database
Google Chrome < 86.0.4240.111 Vulnerable CVE Program (cve.org) e CISA ADP
Netapp Ontap Select Deploy Administration Utility versions not specified by the source Vulnerable NIST National Vulnerability Database
Opensuse Backports Sle version 15.0-sp2 Vulnerable NIST National Vulnerability Database
Nuget CefSharp.Common < 85.3.130 Vulnerable GitHub Security Advisories
Nuget CefSharp.WinForms < 85.3.130 Vulnerable GitHub Security Advisories
Nuget CefSharp.Wpf < 85.3.130 Vulnerable GitHub Security Advisories
Nuget CefSharp.Wpf.HwndHost < 85.3.130 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.6 CVSS 3.1 Critical 2.8 6.0 nvd@nist.gov via NIST National Vulnerability Database
9.6 CVSS 3.1 Critical 2.8 6.0 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
9.6 CVSS 3.1 Critical — — CISA-ADP via CVE Program (cve.org) e CISA ADP
6.5 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
4.3 CVSS 2.0 Medium 8.6 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)
Sources disagree significantly and the divergence is under review. Every score is kept with its origin. For prioritization we use 9.6 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-787 · Out-of-bounds Write

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Nov 3, 2021
Federal deadline
Nov 17, 2021
passed 1795 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Proofs of concept on GitHub

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 16, 2026 · 4 reading(s) · max 63.89%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
  • Hunt retroactively in logs from before Nov 3, 2021 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · nuget/cefsharp.common, nuget/cefsharp.wpf, nuget/cefsharp.winforms, nuget/cefsharp.wpf.hwndhost
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · google/chrome
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Affected products added · google/chrome, freetype/freetype, debian/debian linux, fedoraproject/fedora, opensuse/backports sle, netapp/ontap select
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 9.6
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2021
  • Added to CISA KEV catalog
    Nov 2, 2021 · CISA
  • 2020
  • CVE published
    Nov 3, 2020 · Chrome

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

22 on the record

Elsewhere on this site

Debian
every CVE for this vendor
2021-11
what else CISA listed that month
Memory corruption
same class
CWE-787
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-110922 Use after free in Prerender in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to... 1d
  • CVE-2026-110920 Memory corruption in V8 in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to... 1d
  • CVE-2026-110919 Use after free in V8 in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to execute... 1d
  • CVE-2026-110918 Memory corruption in Core in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to... 1d
  • CVE-2026-110917 Memory corruption in SVG in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to... 1d
  • CVE-2026-110921 Use after free in V8 in Google Chrome prior to 155.0.8059.84 allowed a remote attacker to execute... 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2020-15999 is "Google Chrome FreeType Heap Buffer Overflow Vulnerability", rated Critical. It affects Debian Linux (Debian); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.6 describes technical severity. EPSS 63.89% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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