HDF Group HDF5 up to 2.2.x Local Heap src/H5HL.c H5HL_unprotect null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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3.2$0-$5k0.73+

Summaryinfo

A vulnerability was found in HDF Group HDF5 up to 2.2.x. It has been classified as problematic. This affects the function H5HL_unprotect of the file src/H5HL.c of the component Local Heap. The manipulation leads to null pointer dereference. This vulnerability is documented as CVE-2026-120758. The attack needs to be performed locally. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in HDF Group HDF5 up to 2.2.x and classified as problematic. This issue affects the function H5HL_unprotect of the file src/H5HL.c of the component Local Heap. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HL_unprotect() in src/H5HL.c. H5HL_protect() pins a single metadata cache entry for a local heap, either the heap prefix or the separate data block, and H5HL_unprotect() unpins it on the final unprotect. When the metadata cache destroys a corrupted local heap entry, H5HL__prfx_dest() unlinks it from the heap by setting heap->prfx or heap->dblk to NULL. A crafted HDF5 file can therefore reach H5HL_unprotect() with no cached object to unpin, and the function passes the NULL pointer to H5AC_unpin_entry(). 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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-120758 since 11/02/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

It is declared as proof-of-concept.

Upgrading to version 2.3.0 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.3
VulDB Meta Temp Score: 3.2

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Proof-of-Concept
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: HDF5 2.3.0

Timelineinfo

11/02/2026 CVE reserved
11/03/2026 +1 days Advisory disclosed
11/03/2026 +0 days VulDB entry created
11/03/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CNA: HDFG
CVE: CVE-2026-120758 (🔒)

GCVE (CVE): GCVE-0-2026-120758
GCVE (VulDB): GCVE-100-430421

Entryinfo

Created: 11/03/2026 16:53
Changes: 11/03/2026 16:53 (71)
Complete: 🔍
Cache ID: 216::103

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