CVE-2026-105274 hexpm CVE debrief

Who should care

Defenders responsible for hex_core, hex, and rebar3 deployments should assess exposure and prioritize remediation based on the severity of the vulnerability and the potential impact on their systems.

Why it matters

CVE-2026-105274 is a Data Amplification vulnerability in hex_core that allows an attacker to exhaust the memory of the Erlang VM. Defenders should assess exposure and prioritize remediation based on the severity of the vulnerability and the potential impact on their systems.

• Memory exhaustion attacks may occur if affected versions are not patched or mitigated
• Verify affected versions and apply patches or mitigations to prevent potential memory exhaustion attacks
• Monitor systems for signs of memory exhaustion or unusual activity

Technical summary

The vulnerability is caused by the improper handling of highly compressed data in hex_core, which allows an attacker to exhaust the memory of the Erlang VM. The affected code is vendored in hex and rebar3. The fix for CVE-2026-21619 added the safe option and a check without limiting the size of the decoded term. Defenders should prioritize verifying affected versions and applying patches or mitigations to prevent potential memory exhaustion attacks. The vulnerability affects hex_core, hex, and rebar3, and defenders should assess exposure and prioritize remediation based on the severity of the vulnerability and the potential impact on their systems.

Defensive priority

Defenders should prioritize verifying affected versions and applying patches or mitigations to prevent potential memory exhaustion attacks.

Recommended defensive actions

• Verify affected versions of hex_core, hex, and rebar3 in your environment
• Apply patches or mitigations to prevent potential memory exhaustion attacks
• Monitor systems for signs of memory exhaustion or unusual activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by the improper handling of highly compressed data in hex_core. The affected code is vendored in hex and rebar3. The fix for CVE-2026-21619 added the safe option and a check without limiting the size of the decoded term.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.