NULL pointer dereference in HarfBuzz - CVE-2026-22693
Published: April 28, 2026
Vulnerability identifier: #VU128345
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-22693
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Freedesktop.org
Affected software:
HarfBuzz
HarfBuzz
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a null pointer dereference in OT::SubtableUnicodesCache::create() when processing font subsetting operations. A remote attacker can trigger a memory allocation failure that leads to a null pointer being used with placement new to cause a denial of service.
The issue is triggered when hb_malloc returns NULL, such as in low-memory conditions or with custom allocators that simulate allocation failures, and results in a segmentation fault during hb_subset_preprocess.
How to mitigate CVE-2026-22693
Install security update from vendor's website.