GitHub Advisoryadvisory · Hex

GHSA-hx9w-f2w9-9g96 hex_core has Unsafe Deserialization of Erlang Terms

LOW Published 2026-03-01 Modified 2026-04-06 Official page ↗
Aliases
CVE-2026-21619
Ecosystem
Hex
Packages
hex_core
Severity
Low
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weaknesses
CWE-400
Reviewed
2026-03-01

Affected packages

• Hex hex_core: < 0.12.1 → fixed in 0.12.1

Description

Impact The Hex client (`hex_core`) deserializes Erlang terms received from the Hex API using `binary_to_term/1` without sufficient restrictions. If an attacker can control the HTTP response body returned by the Hex API, this allows denial-of-service attacks such as atom table exhaustion, leading to a VM crash. No released versions are known to allow remote code execution. Patches • https://github.com/hexpm/hex_core/commit/cdf726095bca85ad2549d146df1e831ae93c2b13 • https://github.com/hexpm/hex/commit/636739f3322514e9303ca335fb630696fcbb3c95 • https://github.com/erlang/rebar3/commit/1d4478f527e373de0b225951e53115450e0d9b9d Workarounds Ensure that the Hex API URL (`HEX_API_URL`) points only to trusted endpoints. There is no client-side workaround that fully mitigates this issue without applying the patch. Resources • hex_core Module: https://github.com/hexpm/hex_core/blob/main/src/hex_api.erl • Hex Vendored Module: https://github.com/hexpm/hex/blob/main/src/mix_hex_api.erl • Rebar3 Vendored Module: https://github.com/erlang/rebar3/blob/main/apps/rebar/src/vendored/r3_hex_api.erl • hex_core Patch: https://github.com/hexpm/hex_core/commit/cdf726095bca85ad2549d146df1e831ae93c2b13 • Hex Vendored Patch: https://github.com/hexpm/hex/commit/636739f3322514e9303ca335fb630696fcbb3c95 • Rebar3 Vendored Patch: https://github.com/erlang/rebar3/commit/1d4478f527e373de0b225951e53115450e0d9b9d

Related

Alias · CVE (1)

  • CVE-2026-21619 Uncontrolled Resource Consumption, Deserialization of Untrusted Data vulnerability in hexpm hex_core (hex_api modules), hexpm hex… vulnerability

Weakness · CWE (1)

  • CWE-400 Uncontrolled Resource Consumption weakness

References