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CVE-2026-16599— Denial of Service in GNU wget

Quick assessment

Affected
GNU wget
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

GNU wget是美国GNU基金会开源的一个文件下载工具。 GNU wget 1.25.0及之前版本存在输入验证错误漏洞，该漏洞源于未对FTP挑战行中的序列号进行上界验证，可能允许恶意FTP服务器或网络攻击者发送特制OPIE挑战，导致wget执行大量MD5计算而暂停，造成拒绝服务。

CVSS 5.1 · Medium EPSS 0.38% · P31

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
GNU wget ≤ 1.25.0 affected
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I. Basic Information for CVE-2026-16599

Vulnerability Information
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Vulnerability Title
Denial of Service in GNU wget
Source: CVE Program / CVE List V5
Vulnerability Description
GNU wget is vulnerable to denial of service in its FTP OPIE/S-KEY authentication functionality. The server-supplied sequence number from the FTP challenge line is used as an iteration count for an MD5 key-derivation loop without any upper bound validation. A malicious FTP server or a network attacker positioned to intercept FTP traffic can send a crafted OPIE challenge with a sequence number near INT_MAX, causing wget to perform up to approximately 2.1 billion MD5 computations and suspend for some time. The --timeout option does not mitigate this because it applies only to network I/O, not CPU computation. This issue was fixed in commit e9697d98e7249b0f68a6be040a4f3dcc5bc101fa
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
循环条件输入未经检查
Source: CVE Program / CVE List V5
Vulnerability Title
GNU wget 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
GNU wget是美国GNU基金会开源的一个文件下载工具。 GNU wget 1.25.0及之前版本存在输入验证错误漏洞，该漏洞源于未对FTP挑战行中的序列号进行上界验证，可能允许恶意FTP服务器或网络攻击者发送特制OPIE挑战，导致wget执行大量MD5计算而暂停，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
GNU wget 0 ~ 1.25.0 -

II. Public POCs for CVE-2026-16599

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III. Intelligence Information for CVE-2026-16599

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Patches & Fixes for CVE-2026-16599 (1)

Security Blog Posts for CVE-2026-16599 (1)

Other References for CVE-2026-16599 (1)

IV. Related Vulnerabilities

Same product: wget
Same vendor: GNU
Same weakness: CWE-606