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CVE-2026-42536 is a heap-based buffer overflow in Apache HTTP Server's mod_xml2enc module involving xml2StartParse when processing untrusted content. Apache HTTP Server versions 2.4.0 through 2.4.67 are affected. Processing certain content from an untrusted backend can potentially cause remote denial of service. Version 2.4.68 fixes the vulnerability.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This three-file repository contains a standalone Python proof of concept for CVE-2026-42536, described as a heap-based out-of-bounds write in Apache HTTP Server's mod_xml2enc module. The executable entry point, poc.py, launches a threaded attacker-controlled HTTP payload server, then makes up to ten configurable HTTP requests (three by default) to a vulnerable Apache front end. Its only source code is Python; README.md supplies the vulnerable proxy/filter topology and verification guidance, and .gitattributes only configures line-ending normalization. The payload backend returns a Windows-1252 HTML response with a configurable skipped prefix and a long sequence of byte 0x80. Under xml2StartParse html, the affected module advances its internal buffer pointer past the prefix but allegedly retains the original capacity. CP1252-to-UTF-8 expansion of 0x80 then causes a write beyond the actual remaining allocation. The intended observable result is a crashed Apache child worker and repeatable denial of service, rather than code execution. The script has basic safety controls: it defaults both target and backend binding to loopback and refuses non-loopback addresses unless --allow-remote is explicitly supplied. Parameters allow customization of front-end host/port/path, backend bind/port, prefix size, expansion length, attempts, and timeout. The README states that Apache 2.4.68 corrects the capacity accounting and should serve as a negative control.
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38 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A vulnerability addressed by the referenced Alma Linux 9.6 security advisory; the supplied content provides no technical impact or exploitation details.
A vulnerability addressed by the EulerOS_SA-2026-3834 update for Apache HTTP Server-related packages on Huawei EulerOS UVP 2.10.1.
A vulnerability referenced in the EulerOS SA-2026-3869 security advisory affecting Huawei EulerOS HTTPD-related packages.
A vulnerability addressed by Huawei EulerOS SA-2026-3695; no technical flaw details are provided.
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