CVE-2026-75758
Received Received - Intake

Uncontrolled Recursion in Elixir Standard Library

Vulnerability report for CVE-2026-75758, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: EEF

Description

Uncontrolled Recursion vulnerability in the Elixir standard library allows an attacker who controls a list passed to inspect/1, List.to_string/1, or List.to_charlist/1 to exhaust a BEAM node's memory. Inspect.List's charlist branch in lib/elixir/lib/inspect.ex classifies a list as a charlist using List.ascii_printable?/2, which examines only the first :printable_limit (4096 by default) elements, and then calls IO.chardata_to_string/1 on the whole term. A list whose printable prefix exceeds that limit but which contains a later element that is not a code point (an atom, an out-of-range integer, or an improper tail) is therefore mis-classified, and the conversion raises ArgumentError. That conversion runs inside List.to_string/1, whose rescue clause builds its message by interpolating inspect(list), which re-enters the same branch and raises again. The nested inspection is an argument to raise, so the recursion is not in tail position and every level is retained: the process stack grows monotonically while each cycle re-walks the list, until the process is killed by max_heap_size or, by default, the node runs out of memory. List.to_charlist/1 has the same rescue shape. Below the printable limit the inner inspect/1 sees the invalid element within its counter and renders the list in ordinary bracket form, so a single ArgumentError is raised and no recursion occurs. This issue affects elixir: from 1.15.0-rc.0 before 1.18.5, from 1.19.0-rc.0 before 1.19.6, and from 1.20.0-rc.0 before 1.20.4.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-08-28
Last Modified
2026-08-28
Generated
2026-08-29
AI Q&A
2026-08-28
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
elixir elixir From 1.15.0-rc.0 (inc) to 1.18.5 (exc)
elixir elixir From 1.19.0-rc.0 (inc) to 1.19.6 (exc)
elixir elixir From 1.20.0-rc.0 (inc) to 1.20.4 (exc)
elixir elixir to 1.18.5 (exc)
elixir elixir to 1.19.6 (exc)
elixir elixir to 1.20.4 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-674 The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

Attack-Flow Graph

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Executive Summary

This vulnerability is an uncontrolled recursion issue in Elixir's standard library functions inspect/1, List.to_string/1, and List.to_charlist/1. It occurs when an attacker controls a list with a long printable prefix (over 4096 elements) followed by an invalid element. The system misclassifies such lists as charlists, triggering recursive error handling that exhausts memory by repeatedly inspecting the same list until the BEAM node crashes.

Detection Guidance

To detect this vulnerability, monitor for processes consuming excessive memory when using Elixir's inspect/1, List.to_string/1, or List.to_charlist/1 functions. Check for crashes in BEAM nodes with symptoms like sudden memory exhaustion or process hangs. Use system monitoring tools like top, htop, or ps to observe memory usage spikes in Elixir processes.

Impact Analysis

This vulnerability can cause denial-of-service by crashing Elixir applications or entire BEAM nodes due to memory exhaustion. It may lead to system unavailability, data loss, or service disruption if exploited. Systems processing untrusted input through these functions are particularly vulnerable.

Compliance Impact

This vulnerability primarily impacts system availability, which could violate availability requirements in GDPR (Article 32) and HIPAA (Security Rule). Downtime from crashes may lead to unauthorized access risks or data processing disruptions, potentially breaching compliance obligations for data protection and system reliability.

Mitigation Strategies
  • Upgrade Elixir to patched versions: 1.18.5, 1.19.6, or 20.4 or later to resolve the issue.
  • Set a global inspect function to render charlists as lists by default, preventing the recursion path.
  • Limit process heap size in BEAM nodes to contain memory exhaustion damage.
  • Review and sanitize inputs to inspect/1, List.to_string/1, and List.to_charlist/1 functions to avoid processing untrusted lists.

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