---
id: CVE-2026-111269
title: libical through 4.0.6 Heap Out-of-Bounds Read via icalvalue_decode_ical_string
summary: >-
  libical through 4.0.6 contains a heap-based out-of-bounds read in
  icalvalue_decode_ical_string() in src/libical/icalvalue.c when decoding input
  ending in a backslash. Attackers can supply escaped iCalendar text with a
  trailing backslash,…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: libical
product: libical
affected:
  - libical <= 4.0.6
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T21:43:16.966Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-111269'
references:
  - url: 'https://hackmd.io/@haind-pwn/libical-icalvalue-decode-ical-string-oob-read'
  - url: 'https://github.com/libical/libical/pull/1455'
  - url: >-
      https://github.com/libical/libical/commit/d753885ce2de7c105d6b8c405aa7aee1d98ad8de
  - url: >-
      https://github.com/libical/libical/blob/9cfca65c122fa23b9680a28e0c9225a2fd015fc5/src/libical/icalvalue.c#L1608-L1645
  - url: 'https://github.com/libical/libical'
  - url: >-
      https://www.vulncheck.com/advisories/libical-through-4.0.6-heap-out-of-bounds-read-via-icalvalue-decode-ical-string
    label: >-
      VulnCheck Advisory: libical through 4.0.6 Heap Out-of-Bounds Read via
      icalvalue_decode_ical_string
tags:
  - cve.org
ingestedAt: '2026-10-15T22:48:25.446Z'
---

## Overview

libical through 4.0.6 contains a heap-based out-of-bounds read in icalvalue_decode_ical_string() in src/libical/icalvalue.c when decoding input ending in a backslash. Attackers can supply escaped iCalendar text with a trailing backslash, causing the loop to read past the terminator and crash the application or leak adjacent heap memory.

## Affected

- `libical <= 4.0.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.