Vulnerability · Published Nov 10, 2021 · Assigned by mitre

CVE-2021-43523

Critical 9.6

In plain English

A critical-severity cross-site scripting in the uclibc package (Debian). Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 3.1% (higher than 88% of all known vulnerabilities).

Severity (CVSS 3.1)9.6Critical

Exploit odds (30 days)3.1%top 12.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	uclibc	no fix listed	DEBIAN-CVE-2021-43523
Debian:13	uclibc	no fix listed	DEBIAN-CVE-2021-43523
Debian:14	uclibc	no fix listed	DEBIAN-CVE-2021-43523

Affected products (as reported)

Vendor	Product	Versions
n/a	n/a	n/a

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

References

https://uclibc-ng.org/ x_refsource_MISC
https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174 x_refsource_MISC
https://www.openwall.com/lists/oss-security/2021/11/09/1 x_refsource_MISC