PatchTheCVECVE-2026-26199: HDF5 is a high-performance library and a file format specification that implements the HDF5 data model
CVE-2026-26199 is a medium-severity flaw (CVSS 6.5) affecting hdf5. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If `H5Iget_name` is invoked on a group id with `0` for the size parameter, it will underflow when trying to place a null terminator in the buffer. This can occur if `H5Iget_name` is invoked in a way where `size` can be forced to zero, and there is important data before the `name` buffer.
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.4% (top 72%) |
| CISA exploited list | No |
| Weakness | CWE-124 |
| Published | 2026-07-20 |
| Last modified | 2026-10-24 |
Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-26199?
hdf5: upgrade to 2.1.0. Exact commands for each OS are on this page.
Is CVE-2026-26199 being exploited?
CVE-2026-26199 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-26199 affect?
CVE-2026-26199 affects hdf5. Severity is medium (CVSS 6.5). HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If `H5Iget_name` is invoked on a group id with `0` for the size parameter, it will underflow when trying to place a null terminator in t
How urgent is CVE-2026-26199?
Priority 40/100. Public exploit reference; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-26197 HIGH 7.5 UPGRADE HDF5 is a high-performance library and a file format specification that implements the HDF5 data model
- CVE-2026-17573 MEDIUM 5.5 UPGRADE A double free vulnerability was discovered in the HDF5 library
- CVE-2026-17572 MEDIUM 5.5 UPGRADE Heap-based buffer overflow in the SOHM list-index deserialization code in HDF5 through 2.1.1 on all platforms
- CVE-2026-17574 MEDIUM 5.5 UPGRADE HDF5 contains a NULL pointer dereference vulnerability