CVE-2026-1858: CWE-20 Improper input validation in gnu wget2
CVE-2026-1858 is a medium severity vulnerability in GNU wget2 where the software improperly validates server certificates. Specifically, wget2 accepts TLS server certificates that have incorrect Key Usage (KU) or Extended Key Usage (EKU) attributes. This flaw could allow an attacker who has compromised a certificate issued for a different purpose to reuse it for TLS server authentication, potentially undermining the security of TLS connections. No official patch or remediation guidance is currently available from the vendor. The vulnerability has not been reported as exploited in the wild.
AI Analysis
Technical Summary
GNU wget2 contains an input validation vulnerability (CWE-20) where it accepts server TLS certificates with incorrect Key Usage or Extended Key Usage fields. This improper validation means that certificates intended for other purposes, if compromised along with their private keys, might be reused by attackers to impersonate TLS servers. The CVSS 3.1 base score is 4.8 (medium), reflecting network attack vector, high attack complexity, no privileges required, no user interaction, and limited confidentiality and integrity impact. There is no vendor advisory or patch available at this time, and no known exploits have been reported.
Potential Impact
An attacker who has access to a certificate and private key issued for a purpose other than TLS server authentication could reuse that certificate to impersonate a TLS server to wget2 clients. This could lead to limited confidentiality and integrity impacts during TLS sessions initiated by wget2. The vulnerability does not affect availability and requires high attack complexity with no privileges or user interaction needed.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should be cautious when using wget2 in environments where certificate misuse could be a concern. No vendor-provided mitigation or workaround is currently documented.
CVE-2026-1858: CWE-20 Improper input validation in gnu wget2
Description
CVE-2026-1858 is a medium severity vulnerability in GNU wget2 where the software improperly validates server certificates. Specifically, wget2 accepts TLS server certificates that have incorrect Key Usage (KU) or Extended Key Usage (EKU) attributes. This flaw could allow an attacker who has compromised a certificate issued for a different purpose to reuse it for TLS server authentication, potentially undermining the security of TLS connections. No official patch or remediation guidance is currently available from the vendor. The vulnerability has not been reported as exploited in the wild.
CVSS v3.1
Score 4.8medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
GNU wget2 contains an input validation vulnerability (CWE-20) where it accepts server TLS certificates with incorrect Key Usage or Extended Key Usage fields. This improper validation means that certificates intended for other purposes, if compromised along with their private keys, might be reused by attackers to impersonate TLS servers. The CVSS 3.1 base score is 4.8 (medium), reflecting network attack vector, high attack complexity, no privileges required, no user interaction, and limited confidentiality and integrity impact. There is no vendor advisory or patch available at this time, and no known exploits have been reported.
Potential Impact
An attacker who has access to a certificate and private key issued for a purpose other than TLS server authentication could reuse that certificate to impersonate a TLS server to wget2 clients. This could lead to limited confidentiality and integrity impacts during TLS sessions initiated by wget2. The vulnerability does not affect availability and requires high attack complexity with no privileges or user interaction needed.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should be cautious when using wget2 in environments where certificate misuse could be a concern. No vendor-provided mitigation or workaround is currently documented.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- tenable
- Date Reserved
- 2026-02-03T20:13:53.718Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f26bc7cbff5d861048aa2b
Added to database: 4/29/2026, 8:36:23 PM
Last enriched: 5/7/2026, 2:11:29 AM
Last updated: 6/14/2026, 7:22:49 AM
Views: 52
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