Bug 2515609

Summary: CVE-2026-19028 hdf5: HDF5: Denial of Service via integer underflow in Fletcher32 filter [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Joel Chamberlain <jochambe>
Component: hdf5Assignee: Orion Poplawski <orion>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: epel10CC: igor.raits, orion, sagitterghostproton.me, scitech-bugs
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["d691c9ba-4f1f-4f32-bdc9-3a284d5c345b"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2511855    

Description Joel Chamberlain 2026-08-13 19:50:30 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

H5Z__filter_fletcher32 in H5Zfletcher32.c in HDF5 through 2.3.0 computes the data length to checksum by subtracting the 4-byte trailing checksum size from the input buffer size without checking that the buffer is at least 4 bytes, allowing a size_t underflow. This allows attackers to cause a denial of service (massively out-of-bounds read and application crash in H5_checksum_fletcher32) via a crafted HDF5 file with a Fletcher32-filtered chunk smaller than 4 bytes, triggered via H5Dread, e.g. by the h5ls or h5dump tools.