CVE-2026-21619 Unsafe Deserialization of Erlang Terms in hex_core
Attackers can cause denial of service or execute code via unsafe deserialization of Erlang terms in hex_core, hex, and rebar3.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-21619?
CVE-2026-21619 is a low-severity unsafe deserialization vulnerability in erlang hex, published on 27 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Uncontrolled Resource Consumption, Deserialization of Untrusted Data vulnerability in hexpm hex_core (hex_api modules), hexpm hex (mix_hex_api modules), erlang rebar3 (r3_hex_api modules) allows Object Injection, Excessive Allocation. This vulnerability is associated with program files src/hex_api.erl, src/mix_hex_api.erl, apps/rebar/src/vendored/r3_hex_api.erl and program routines hex_core:request/4, mix_hex_api:request/4, r3_hex_api:request/4.
This issue affects hex_core: from 0.1.0 before 0.12.1; hex: from 2.3.0 before 2.3.2; rebar3: from 3.9.1 before 3.27.0.
Which versions are affected by CVE-2026-21619?
3 open source packages ship an affected version, including hex_core. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
hex_core Hex | All versions | 0.12.1 |
hex_core Hex | All versions | 0.12.1 |
hex_core Hex | From 0.1.0 | 0.12.1 |
Products include Erlang Rebar3, Hex Hex, Hex Hex Core.
How do I fix CVE-2026-21619?
Upgrade hex_core to 0.12.1 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-21619 being exploited?
There is no known exploitation of CVE-2026-21619 in the wild and no public exploit code.
Other vulnerabilities in erlang hex
Sources
Also known as DEBIAN-CVE-2026-21619, EEF-CVE-2026-21619, GHSA-hx9w-f2w9-9g96, MGASA-2026-0196, UBUNTU-CVE-2026-21619.