Google Chrome FreeType Heap Buffer Overflow
CVE-2020-15999 is a critical-severity out-of-bounds write vulnerability in Chrome from Google, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 86.0.4240.111 as the first without the flaw, so updating Chrome to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Chrome to 86.0.4240.111 or a later version.
- Update Freetype to 2.10.4 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Chrome | before 86.0.4240.111 | 86.0.4240.111 | |
| Freetype | Freetype | 2.6.0 up to, but not including, 2.10.4 | 2.10.4 |
| Debian | Debian Linux | 10.0 | Not stated |
| Fedora Project | Fedora | 31 | Not stated |
| openSUSE | Backports Sle | 15.0 | Not stated |
| NetApp | Ontap Select Deploy Administration Utility | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.6 | Critical | NVD |
| CVSS 3.1 | 9.6 | Critical | CISA (ADP) |
| CVSS 2.0 | 4.3 | Medium | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- seclists.org/fulldisclosure/2020/Nov/33Mailing List, Not Applicable, Third Party Advisory
- chromereleases.googleblog.com/2020/10/stable-channel-update-for-desktop_20.htmlThird Party Advisory
- security.gentoo.org/glsa/202011-12Third Party Advisory
- security.gentoo.org/glsa/202012-04Third Party Advisory
- security.gentoo.org/glsa/202401-19Third Party Advisory
- debian.org/security/2021/dsa-4824Mailing List, Third Party Advisory
- security.netapp.com/advisory/ntap-20240812-0001/Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-15999US Government Resource
Technical write-ups (may include proof of concept)
- crbug.com/1139963Exploit, Issue Tracking, Third Party Advisory
- googleprojectzero.blogspot.com/p/rca-cve-2020-15999.htmlExploit, Third Party Advisory
Other vulnerabilities in Chrome
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent Out-of-bounds Write vulnerabilities
- 9.6 Critical severity
- 8.8 High severity
Google Chromium V8 Type Confusion Exploited
- 10.0 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
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