OSV-2026-595 UNKNOWN WRITE in std::__1::istreambuf_iterator<char, std::__1::char_traits<char>> std::__1::num_g

Not scored Published

A memory corruption vulnerability in the C++ standard library's input stream handling can cause a crash when parsing specific data.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Not stated
Victim action needed
Not needed
Fix
None listed

What is OSV-2026-595?

OSV-2026-595 is a memory corruption vulnerability in libigl, published on 20 Apr 2026.

Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=504141064

Crash type: UNKNOWN WRITE
Crash state:
std::__1::istreambuf_iterator&lt;char, std::__1::char_traits&lt;char&gt;&gt; std::__1::num_g
std::__1::basic_istream&lt;char, std::__1::char_traits&lt;char&gt;&gt;&amp; std::__1::__input_ar
igl::MshLoader::parse_element_field

Which versions are affected by OSV-2026-595?

1 open source package ship an affected version, including libigl.

PackageAffectedFixed in
libigl OSS-FuzzAll versionsNone

How do I fix OSV-2026-595?

No fix has been published for OSV-2026-595 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is OSV-2026-595 being exploited?

There is no known exploitation of OSV-2026-595 in the wild and no public exploit code.

Sources

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