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Vulnerability · Published Jan 10, 2026 · Assigned by GitHub_M

CVE-2026-22693Null Pointer Dereference in SubtableUnicodesCache::create leading to DoS

Medium 5.3

In plain English

A medium-severity null pointer dereference in harfbuzz from harfbuzz. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.5%top 60.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

HarfBuzz is a text shaping engine. Prior to version 12.3.0, a null pointer dereference vulnerability exists in the SubtableUnicodesCache::create function located in src/hb-ot-cmap-table.hh. The function fails to check if hb_malloc returns NULL before using placement new to construct an object at the returned pointer address. When hb_malloc fails to allocate memory (which can occur in low-memory conditions or when using custom allocators that simulate allocation failures), it returns NULL. The code then attempts to call the constructor on this null pointer using placement new syntax, resulting in undefined behavior and a Segmentation Fault. This issue has been patched in version 12.3.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12harfbuzzno fix listedDEBIAN-CVE-2026-22693
Debian:13harfbuzz10.2.0-1+deb13u1DEBIAN-CVE-2026-22693
Debian:14harfbuzz12.3.0-4DEBIAN-CVE-2026-22693
Ubuntu:24.04:LTSharfbuzzno fix listedUBUNTU-CVE-2026-22693
Ubuntu:25.10harfbuzzno fix listedUBUNTU-CVE-2026-22693

Affected products (as reported)

VendorProductVersions
harfbuzz harfbuzz < 12.3.0

Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References