CVE-2021-42694
What it is
An issue was discovered in the character definitions of the Unicode Specification through 14.0. The specification allows an adversary to produce source code identifiers such as function names using homoglyphs that render visually identical to a target identifier. Adversaries can leverage this to inject code via adversarial identifier definitions in upstream software dependencies invoked deceptively in downstream software. NOTE: the Unicode Consortium offers the following alternative approach to presenting this concern. An issue is noted in the nature of international text that can affect applications that implement support for The Unicode Standard (all versions). Unless mitigated, an adversary could produce source code identifiers using homoglyph characters that render visually identical to but are distinct from a target identifier. In this way, an adversary could inject adversarial identifier definitions in upstream software that are not detected by human reviewers and are invoked deceptively in downstream software. The Unicode Consortium has documented this class of security vulnerability in its document, Unicode Technical Report #36, Unicode Security Considerations. The Unicode Consortium also provides guidance on mitigations for this class of issues in Unicode Technical Standard #39, Unicode Security Mechanisms.
At a glance
- Exploitability
- Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 4.9% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 4.9% in the next 30 days (EPSS).
- Severity: 8.3 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 4.9% · EPSS, next 30 days
- Weakness
- CWE-94 · Code injection
- Record status
- Modified
Affected
- Unicode < 14.0.0
Attack profile CVSS 3.1 · 8.3
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-42694.md and follow it. Check whether this project is affected by CVE-2021-42694. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- http://www.unicode.org/versions/Unicode14.0.0/
- https://www.unicode.org/reports/tr36/
- https://www.unicode.org/reports/tr39/
- http://www.unicode.org/versions/Unicode14.0.0/
- https://www.unicode.org/reports/tr36/
- https://www.unicode.org/reports/tr39/
References
- http://www.openwall.com/lists/oss-security/2021/11/01/1
- http://www.openwall.com/lists/oss-security/2021/11/01/6
- http://www.unicode.org/versions/Unicode14.0.0/
- https://cwe.mitre.org/data/definitions/1007.html
- https://security.gentoo.org/glsa/202210-09
- https://trojansource.codes
- https://www.kb.cert.org/vuls/id/999008
- https://www.scyon.nl/post/trojans-in-your-source-code
- https://www.unicode.org/reports/tr36/
- https://www.unicode.org/reports/tr39/
- http://www.openwall.com/lists/oss-security/2021/11/01/1
- http://www.openwall.com/lists/oss-security/2021/11/01/6
- http://www.unicode.org/versions/Unicode14.0.0/
- https://cwe.mitre.org/data/definitions/1007.html
- https://security.gentoo.org/glsa/202210-09
- https://trojansource.codes
- https://www.kb.cert.org/vuls/id/999008
- https://www.scyon.nl/post/trojans-in-your-source-code
- https://www.unicode.org/reports/tr36/
- https://www.unicode.org/reports/tr39/