CVE-2025-6856: HDF5 H5FL.c H5FL__reg_gc_list use after free
CSIRTS triage
- What
- The H5FL.c file contains a use-after-free vulnerability in the H5FL__reg_gc_list function.
- Who is affected
- Applications using HDF5 libraries that process crafted HDF5 files.
- Urgency
- Low severity (CVSS 3.3); limited exploitability but memory corruption is possible.
- Action
- Update HDF5 to a patched version addressing the use-after-free in H5FL__reg_gc_list.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-6856
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2025-68560.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2025-6856 | coverage & exploitation status | NVD · CVE.org |
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