CVE-2026-84446 Denial of service in libheif
Crafted HEIF files cause infinite loops and memory exhaustion in libheif, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-84446?
CVE-2026-84446 is a high-severity denial of service vulnerability in strukturag libheif, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
libheif is a HEIF and AVIF file format decoder and encoder. Prior to 1.23.2, crafted HEIF sequence timing and edit-list data can make Track::init_sample_timing_table() compute a logical m_num_output_samples value that exceeds the uint32_t counters used by Track_Visual::decode_next_image_sample() and Track::get_next_sample_raw_data(). The resulting comparison can never reach the oversized output count, causing non-terminating decode or raw-sample loops and bypassing max_sequence_frames. The same sequence path repeatedly calls Box_stts::get_sample_duration() and allocates Chunk::m_sample_ranges and Track::m_presentation_timeline outside MemoryHandle accounting, allowing severe CPU and memory exhaustion from a small file. This issue is fixed in version 1.23.2.
Weakness: CWE-835
Which versions are affected by CVE-2026-84446?
How do I fix CVE-2026-84446?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-84446 being exploited?
There is no known exploitation of CVE-2026-84446 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-84446, DEBIAN-CVE-2026-84446, ECHO-e3fa-3f8e-978c, GHSA-xw34-mjcp-jqh8, MINI-8fq3-gvvq-5q9f, ROOT-OS-DEBIAN-12-CVE-2026-84446 and 1 more.