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CVE-2026-120758

NULL Pointer Dereference in H5HL_unprotect via Corrupted File

5.4 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Passive

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.14%Unchanged since Nov 4, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.4

NULL Pointer Dereference in H5HL_unprotect via Corrupted File

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.

Record
CVE-2026-120758
CVSS 4.0
5.4 MediumCVSS: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
Weakness
CWE-476
Updated
2026-11-03
EUVDEUVD-2026-116017 5.4

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.

Record
EUVD-2026-116017
CVSS 4.0
5.4 MediumCVSS: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
Updated
2026-11-03
GitHub AdvisoriesGHSA-49fv-ggjg-jcjc 5.4

HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HL_unprotect() in src...

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.

Record
GHSA-49fv-ggjg-jcjc
CVSS 4.0
5.4 MediumCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-476
Updated
2026-11-03
NVD 5.4

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.

Record
CVE-2026-120758
CVSS 4.0
5.4 MediumCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-476
Updated
2026-11-04
OSV 5.4

NULL Pointer Dereference in H5HL_unprotect via Corrupted File

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.

Record
CVE-2026-120758
CVSS 4.0
5.4 MediumCVSS: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
Weakness
CWE-476
Updated
2026-11-05
OSVDEBIAN-CVE-2026-120758 5.5

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.

Record
DEBIAN-CVE-2026-120758
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-04
OSVUBUNTU-CVE-2026-120758 5.4

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.

Record
UBUNTU-CVE-2026-120758
CVSS 4.0
5.4 MediumCVSS: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
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-05
OSVAZL-112640 No score

CVE-2026-120758 affecting package hdf5 1.14.6-6

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.

Record
AZL-112640
Updated
2026-11-05

Affected products

Affected packages

Affected packages
PackageAffectedFixed
hdf5
Azure Linux:3
 through 1.14.6-6 None known
hdf5
Debian:12
 All versions, plus listed versions
1.10.10+repack-11.10.10+repack-21.10.10+repack-31.10.10+repack-3.11.10.10+repack-3.2
Show 45 moreShow less
1.10.10+repack-3.2+ports1.10.10+repack-3.31.10.10+repack-41.10.10+repack-51.10.8+repack1-11.12.0+repack-1~exp11.12.0+repack-1~exp21.12.2+repack-1~exp11.14.3+repack-1~exp11.14.3+repack1-1~exp21.14.3+repack1-1~exp31.14.4.3+repack-1~exp11.14.4.3+repack-1~exp21.14.4.3+repack-1~exp31.14.5+repack-11.14.5+repack-1~exp11.14.5+repack-1~exp21.14.5+repack-1~exp31.14.5+repack-1~exp41.14.5+repack-1~exp51.14.5+repack-1~exp61.14.5+repack-21.14.5+repack-31.14.5+repack-3.11.14.5+repack-3~exp11.14.5+repack-3~exp21.14.5+repack-3~exp31.14.5+repack-3~exp41.14.5+repack-41.14.5+repack-4~exp11.14.5+repack-4~exp21.14.5+repack-5~exp21.14.5+repack-5~exp31.14.6+repack-11.14.6+repack-1~exp11.14.6+repack-1~exp101.14.6+repack-1~exp111.14.6+repack-1~exp121.14.6+repack-1~exp131.14.6+repack-1~exp141.14.6+repack-1~exp151.14.6+repack-1~exp161.14.6+repack-1~exp171.14.6+repack-1~exp181.14.6+repack-1~exp19
 None known
hdf5
Debian:13
 All versions, plus listed versions
1.14.5+repack-31.14.5+repack-3.11.14.5+repack-41.14.5+repack-4~exp11.14.5+repack-4~exp2
Show 42 moreShow less
1.14.5+repack-5~exp21.14.5+repack-5~exp31.14.6+repack-11.14.6+repack-1~exp11.14.6+repack-1~exp101.14.6+repack-1~exp111.14.6+repack-1~exp121.14.6+repack-1~exp131.14.6+repack-1~exp141.14.6+repack-1~exp151.14.6+repack-1~exp161.14.6+repack-1~exp171.14.6+repack-1~exp181.14.6+repack-1~exp191.14.6+repack-1~exp21.14.6+repack-1~exp201.14.6+repack-1~exp211.14.6+repack-1~exp31.14.6+repack-1~exp41.14.6+repack-1~exp51.14.6+repack-1~exp61.14.6+repack-1~exp71.14.6+repack-1~exp81.14.6+repack-1~exp91.14.6+repack-21.14.6+repack-3~exp12.1.0+repack-12.1.0+repack-1~exp102.1.0+repack-1~exp112.1.0+repack-1~exp32.1.0+repack-1~exp42.1.0+repack-1~exp52.1.0+repack-1~exp62.1.0+repack-1~exp72.1.0+repack-1~exp82.1.0+repack-1~exp92.2.0+repack-12.2.0+repack-22.2.0+repack-32.2.0+repack-42.2.0+repack-52.2.0+repack-6
 None known
hdf5
Debian:14
 All versions, plus listed versions
1.14.5+repack-31.14.5+repack-3.11.14.5+repack-41.14.5+repack-4~exp11.14.5+repack-4~exp2
Show 42 moreShow less
1.14.5+repack-5~exp21.14.5+repack-5~exp31.14.6+repack-11.14.6+repack-1~exp11.14.6+repack-1~exp101.14.6+repack-1~exp111.14.6+repack-1~exp121.14.6+repack-1~exp131.14.6+repack-1~exp141.14.6+repack-1~exp151.14.6+repack-1~exp161.14.6+repack-1~exp171.14.6+repack-1~exp181.14.6+repack-1~exp191.14.6+repack-1~exp21.14.6+repack-1~exp201.14.6+repack-1~exp211.14.6+repack-1~exp31.14.6+repack-1~exp41.14.6+repack-1~exp51.14.6+repack-1~exp61.14.6+repack-1~exp71.14.6+repack-1~exp81.14.6+repack-1~exp91.14.6+repack-21.14.6+repack-3~exp12.1.0+repack-12.1.0+repack-1~exp102.1.0+repack-1~exp112.1.0+repack-1~exp32.1.0+repack-1~exp42.1.0+repack-1~exp52.1.0+repack-1~exp62.1.0+repack-1~exp72.1.0+repack-1~exp82.1.0+repack-1~exp92.2.0+repack-12.2.0+repack-22.2.0+repack-32.2.0+repack-42.2.0+repack-52.2.0+repack-6
 None known
hdf5
Ubuntu:Pro:14.04:LTS
 All versions, plus listed versions
1.8.11-3ubuntu11.8.11-5ubuntu11.8.11-5ubuntu21.8.11-5ubuntu61.8.11-5ubuntu71.8.11-5ubuntu7.11.8.11-5ubuntu7.1+esm11.8.11-5ubuntu7.1+esm2
 None known
hdf5
Ubuntu:Pro:16.04:LTS
 All versions, plus listed versions
1.8.15-patch1+docs-41.8.15-patch1+docs-51.8.16+docs-11.8.16+docs-21.8.16+docs-3
Show 6 moreShow less
1.8.16+docs-3ubuntu11.8.16+docs-41.8.16+docs-4ubuntu11.8.16+docs-4ubuntu1.11.8.16+docs-4ubuntu1.1+esm11.8.16+docs-4ubuntu1.1+esm2
 None known
hdf5
Ubuntu:Pro:18.04:LTS
 All versions, plus listed versions
1.10.0-patch1+docs-41.10.0-patch1+docs-4ubuntu0.1~esm11.10.0-patch1+docs-4ubuntu0.1~esm2
 None known
hdf5
Ubuntu:Pro:20.04:LTS
 All versions, plus listed versions
1.10.4+repack-101.10.4+repack-111.10.4+repack-11ubuntu11.10.4+repack-11ubuntu1+esm1
 None known
hdf5
Ubuntu:22.04:LTS
 All versions, plus listed versions
1.10.6+repack-51.10.7+repack-4ubuntu11.10.7+repack-4ubuntu2
 None known
hdf5
Ubuntu:24.04:LTS
 All versions, plus listed versions
1.10.8+repack1-1ubuntu11.10.10+repack-3ubuntu11.10.10+repack-3.1ubuntu31.10.10+repack-3.1ubuntu4
 None known
hdf5
Ubuntu:26.10
 All versions, plus listed versions
1.14.6+repack-22.2.0+repack-42.2.0+repack-5
 None known
hdf5
Ubuntu:26.04:LTS
 All versions, plus listed versions
1.14.5+repack-3build11.14.5+repack-41.14.6+repack-2
 None known

History

History
RecordedChangedSources
affected, aliases, referencesOSV
affected, aliases, referencesOSV
referencesOSV
referencesGitHub Advisories, NVD
publishedEUVD
publishedEUVD, NVD
aliases, referencesCVE List, GitHub Advisories, NVD
aliases, products, publishedEUVD
first indexedCVE List

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-120758 is a medium vulnerability (CVSS 5.4) in Hdfgroup Hdf5, published November 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.14%, the 3rd percentile. No source names a fixed version.

References

This page doesn't list everything

Left out here: 28 versions. The JSON record has them.

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