Vulnerability Details : CVE-2021-42694
Potential exploit
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.
Products affected by CVE-2021-42694
- cpe:2.3:a:unicode:unicode:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-42694
12.47%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 93 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-42694
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
5.1
|
MEDIUM | AV:N/AC:H/Au:N/C:P/I:P/A:P |
4.9
|
6.4
|
NIST | |
8.3
|
HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
1.6
|
6.0
|
134c704f-9b21-4f2e-91b3-4a467353bcc0 | 2024-08-01 |
8.3
|
HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
1.6
|
6.0
|
NIST |
CWE ids for CVE-2021-42694
-
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.Assigned by: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
-
The product displays information or identifiers to a user, but the display mechanism does not make it easy for the user to distinguish between visually similar or identical glyphs (homoglyphs), which may cause the user to misinterpret a glyph and perform an unintended, insecure action.Assigned by: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
References for CVE-2021-42694
-
https://www.unicode.org/reports/tr39/
UTS #39: Unicode Security MechanismsTechnical Description;Vendor Advisory
-
https://security.gentoo.org/glsa/202210-09
Rust: Multiple Vulnerabilities (GLSA 202210-09) — Gentoo securityThird Party Advisory
-
http://www.unicode.org/versions/Unicode14.0.0/
Unicode 14.0.0Release Notes;Vendor Advisory
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https://trojansource.codes
Trojan Source AttacksThird Party Advisory
-
https://www.kb.cert.org/vuls/id/999008
VU#999008 - Compilers permit Unicode control and homoglyph charactersThird Party Advisory;US Government Resource
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https://www.unicode.org/reports/tr36/
UTR #36: Unicode Security ConsiderationsTechnical Description;Vendor Advisory
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http://www.openwall.com/lists/oss-security/2021/11/01/6
oss-security - Trojan Source AttacksMailing List;Third Party Advisory
-
http://www.openwall.com/lists/oss-security/2021/11/01/1
oss-security - CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source codeMailing List;Third Party Advisory
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https://cwe.mitre.org/data/definitions/1007.html
CWE - CWE-1007: Insufficient Visual Distinction of Homoglyphs Presented to User (4.7)Third Party Advisory
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https://www.scyon.nl/post/trojans-in-your-source-code
Trojans in your source codeExploit;Third Party Advisory
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