CVE-2026-49337 libde265 has an unbounded memory leak via orphaned slice headers in `read_slice_NAL`
A crafted H.265 video stream causes unbounded memory growth in libde265, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-49337?
CVE-2026-49337 is a medium-severity denial of service vulnerability in strukturag libde265, published on 19 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
libde265 is an open source implementation of the h.265 video codec. Prior to version 1.0.20, a crafted sequence of H.265 NAL units causes `decoder_context::read_slice_NAL()` (`libde265/decctx.cc:481`) to attach slice headers to a finished picture object that has no active image unit, resulting in attacker-controlled unbounded heap growth. The retained headers are never freed until the picture is released, which may not happen during continuous streaming. Version 1.0.20 patches the issue.
Weakness: CWE-770
Which versions are affected by CVE-2026-49337?
How do I fix CVE-2026-49337?
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-2026-49337 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49337 exists.
Sources
Also known as ALPINE-CVE-2026-49337, BELL-CVE-2026-49337, DEBIAN-CVE-2026-49337, ECHO-5828-cc38-dea2, GHSA-g5hj-rf9f-7vxm, MINI-rwx6-5mxq-34fm and 2 more.