CVE-2021-43523
9.6
CRITICAL · CVSS 3.1 · EPSS 3.1% (pctl 87)
In your normal cycle
Critical by CVSS (9.6), but no sign of active exploitation.
Description
In uClibc and uClibc-ng before 1.0.39, incorrect handling of special characters in domain names returned by DNS servers via gethostbyname, getaddrinfo, gethostbyaddr, and getnameinfo can lead to output of wrong hostnames (leading to domain hijacking) or injection into applications (leading to remote code execution, XSS, applications crashes, etc.). In other words, a validation step, which is expected in any stub resolver, does not occur.
Scoring
| CVSS | 9.6 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H |
| EPSS | 3.07% — more likely to be exploited than 87% of all CVEs |
| Weakness | CWE-79 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2021-11-10 |
| Last modified | 2026-06-17 |
Affected (2)
| Vendor | Product |
|---|---|
| uclibc | uclibc |
| uclibc-ng project | uclibc-ng |
References
- https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174
- https://uclibc-ng.org/
- https://www.openwall.com/lists/oss-security/2021/11/09/1
- https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174
- https://uclibc-ng.org/
- https://www.openwall.com/lists/oss-security/2021/11/09/1
→ the Explorer · watch your stack · NVD