XSS in Uclibc
CVE-2021-43523
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.031 (87.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 87.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.032 · newest: 0.031 · change: -0.002
Affected products
Weakness classification (CWE)
References
- uclibc-ng.org/ (Vendor Advisory)
- github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174 (Patch, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/11/09/1 (Exploit, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-43523?
- CVE-2021-43523 is a critical-severity vulnerability in Uclibc, classified under Cross-site Scripting. CVSS score: 9.6/10. Published 2021-11-10.
- How severe is CVE-2021-43523?
- Critical severity. CVSS v3 base score is 9.6 out of 10.