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
02 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
03 Exploitation and scoring
- 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.
- EPSS probability
- 3.07% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 87.4% of scored records. A rank, not a probability.
- NVD base score
- 9.6 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/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
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
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.
04 Metadata
- Published
- 2021-11-10 14:03Z4 YR AGO
- Last updated
- 2025-05-05 16:46Z1 YR AGO
- Reserved
- 2021-11-08
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- Critical (CVSS 9.6)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Weaknesses
- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base
- Data version
- 5.1
- Document digest
- 71aee2abfd8e471e7e1a787fa0582abad625ffcc04fb28a9cd140dc68c17dbc5
05 Affected products
06 References
07 Fixed in
Debian 12
- uclibc No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- uclibc No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- uclibc No fix yet
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.