Denial of Service in Expat libexpat via excessive memory allocation
CVE-2025-59375 is a denial-of-service vulnerability in libexpat, the XML parsing library in Expat, affecting versions prior to 2.7.2. A specially crafted small XML document can drive the parser into disproportionately large dynamic memory allocations during parsing. The issue is described as forced extensive use of dynamic memory despite small parser input, indicating insufficient limits or throttling on resource allocation in affected parsing code paths. This can cause the consuming process to allocate far more heap memory than expected while handling attacker-controlled XML input.
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Impact, mitigation & remediation
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Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
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Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
36 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Sandbox escape via logic flaw; fixed with improved checks.
A denial-of-service vulnerability in libexpat caused by insufficient controls on dynamic memory allocation when parsing crafted XML documents, leading to excessive heap allocation and resource exhaustion.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.