Is there a public exploit for CVE-2026-120758?

No public exploit for CVE-2026-120758 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-120758?

CVE-2026-120758 scores CVSS 5.4 (v4.0), rated medium.

What does CVE-2026-120758 affect?

CVE-2026-120758 affects The HDF Group HDF5.

5.4 Medium

HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HLunprotect() in src/H5HL.c.

CVE-2026-120758

HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HLunprotect() in src/H5HL.c. H5HLprotect() pins a single metadata cache entry for a local heap, either the heap prefix or the separate data block, and H5HLunprotect() unpins it on the final unprotect. When the metadata cache destroys a corrupted local heap entry, H5HLprfxdest() unlinks it from the heap by setting heap->prfx or heap->dblk to NULL. A crafted HDF5 file can therefore reach H5HLunprotect() with no cached object to unpin, and the function passes the NULL pointer to H5ACunpinentry(). This causes an assertion failure in debug builds and a NULL pointer dereference and crash in release builds. An attacker who can get a user or application to open and traverse a malicious file can cause a denial of service.

Assessment

CVSS: 5.4 (v4.0)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 3 November 2026
Last updated: 3 November 2026
Affected: The HDF Group · HDF5
Assigner: HDFG

CVSS vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

At the source

EUVD (ENISA)

References

https://github.com/HDFGroup/hdf5/pull/6377

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