CVE-2021-42574

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

12.88% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 96.0% of scored records. A rank, not a probability.

NVD base score

8.3 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-11-01 00:00Z4 YR AGO

Last updated

2024-08-04 03:38Z2 YR AGO

Reserved

2021-10-18

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-94Improper Control of Generation of Code ('Code Injection')Base
• CWE-838Inappropriate Encoding for Output ContextBase

Data version

5.1

Document digest

6282b0cb3b4c95f48ac701496b1db54255cdca07a8bb1e7a0c78a1ad2e07697a

• www.unicode.orghttp://www.unicode.org/versions/Unicode14.0.0/
• trojansource.codeshttps://trojansource.codes
• www.openwall.com[oss-security] 20211101 CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source codehttp://www.openwall.com/lists/oss-security/2021/11/01/1mailing-list
• www.openwall.com[oss-security] 20211101 Re: CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source codehttp://www.openwall.com/lists/oss-security/2021/11/01/4mailing-list
• www.openwall.com[oss-security] 20211101 Trojan Source Attackshttp://www.openwall.com/lists/oss-security/2021/11/01/6mailing-list
• www.openwall.com[oss-security] 20211102 Re: CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source codehttp://www.openwall.com/lists/oss-security/2021/11/01/5mailing-list
• www.openwall.com[oss-security] 20211102 Re: Trojan Source Attackshttp://www.openwall.com/lists/oss-security/2021/11/02/10mailing-list
• lists.fedoraproject.orgFEDORA-2021-0578e23912https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/vendor-advisory
• lists.fedoraproject.orgFEDORA-2021-7ad3a01f6ahttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/vendor-advisory
• www.kb.cert.orgVU#999008https://www.kb.cert.org/vuls/id/999008third-party-advisory
• lists.fedoraproject.orgFEDORA-2021-443139f67chttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/vendor-advisory
• www.scyon.nlhttps://www.scyon.nl/post/trojans-in-your-source-code
• www.unicode.orghttps://www.unicode.org/reports/tr36/
• www.unicode.orghttps://www.unicode.org/reports/tr39/
• www.unicode.orghttps://www.unicode.org/reports/tr31/
• www.unicode.orghttps://www.unicode.org/reports/tr9/tr9-44.html#HL4
• www.starwindsoftware.comhttps://www.starwindsoftware.com/security/sw-20220804-0002/
• security.gentoo.orgGLSA-202210-09https://security.gentoo.org/glsa/202210-09vendor-advisory