CVE-2026-58472 in wget
Summary
by MITRE • 07/07/2026
GNU Wget through 1.25.0, fixed in commit dd692d9, contains a heap buffer overflow vulnerability in the html_quote_string() function in src/convert.c that allows a remote attacker to trigger memory corruption by supplying a crafted HTML attribute with a large number of characters requiring entity encoding. A server-supplied HTML attribute causes a signed integer counter to overflow during output size accumulation, resulting in an undersized heap allocation and subsequent heap buffer overflow during the copy phase.
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Analysis
by VulDB Data Team • 07/07/2026
The vulnerability under discussion represents a critical heap buffer overflow flaw in GNU Wget version 1.25.0 and earlier, which stems from improper handling of HTML attribute encoding within the html_quote_string() function located in src/convert.c. This issue arises when wget processes server-supplied HTML content that contains attributes with excessive character counts requiring entity encoding, creating conditions that lead to memory corruption through integer overflow exploitation. The flaw operates by causing a signed integer counter to overflow during the calculation of output buffer size requirements, resulting in an insufficient heap allocation that subsequently triggers a buffer overflow when data is copied into the undersized memory region.
The technical implementation of this vulnerability involves a specific code path where wget encounters HTML attributes containing large numbers of characters that require entity encoding such as ampersand, quote, or less-than characters. During the conversion process, the html_quote_string() function accumulates the required output size using a signed integer variable that eventually overflows when dealing with extremely long attribute values. This overflow causes the system to allocate a heap buffer that is significantly smaller than the actual data that needs to be written into it, creating a classic heap-based buffer overflow condition.
From an operational perspective this vulnerability presents significant security implications for any system running affected versions of GNU Wget, particularly in environments where wget processes untrusted HTML content from web servers or other network sources. Remote attackers can exploit this flaw by crafting malicious HTML responses that contain specially formatted attributes with excessive character counts, potentially leading to arbitrary code execution, denial of service conditions, or information disclosure. The vulnerability affects both command-line and automated wget operations, making it particularly dangerous in server environments where wget is used for web scraping, automated content retrieval, or as part of larger security toolchains.
The exploitation of this heap buffer overflow aligns with common attack patterns documented in the attack technique framework, specifically relating to memory corruption vulnerabilities that can be leveraged for privilege escalation or system compromise. This flaw demonstrates characteristics consistent with CWE-121 heap-based buffer overflow conditions where insufficient bounds checking leads to memory corruption. The vulnerability also represents a security gap in input validation and size calculation procedures within the HTML processing pipeline of wget, highlighting the importance of robust integer overflow protection mechanisms in network utility applications that handle untrusted data.
Mitigation strategies for this vulnerability include immediate deployment of patched versions of GNU Wget from commit dd692d9 onwards, which properly addresses the integer overflow condition by implementing appropriate bounds checking and size validation before heap allocation. System administrators should also consider implementing network-level restrictions or proxy configurations to limit wget's exposure to untrusted HTML content when possible. Additionally, organizations should perform comprehensive vulnerability assessments of their wget usage patterns and ensure that all systems using wget are regularly updated with security patches to prevent exploitation of this and similar memory corruption vulnerabilities.
The vulnerability serves as a reminder of the critical importance of proper integer overflow protection in network utilities and web clients, particularly in applications that process untrusted input from external sources. Security teams should implement regular patch management processes for core system utilities and consider automated monitoring for vulnerable wget installations within their environments. The flaw also underscores the necessity of thorough code review processes focusing on memory allocation and size calculation logic, as these areas remain common sources of exploitable buffer overflow conditions in widely deployed network applications.