CyberSecBulletin
CVE-2026-84384NVD status: Deferred

libheif: Improper Handling of Highly Compressed Data (Data Amplification)

Published Updated By the CyberSecBulletin desk

CVE-2026-84384 is a high-severity improper handling of highly compressed data (data amplification) vulnerability in libheif from Strukturag, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected libheif versions: >= 1.19.0, < 1.23.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of libheif you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Strukturaglibheif>= 1.19.0, < 1.23.2Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (github.com).

Official description

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause decompress_brotli() and do_inflate() to grow accumulated output without an effective size limit or MemoryHandle accounting. The brotli path has no output bound, while the zlib path checks only a small temporary buffer in a branch that valid streams do not reach, and overlapping icef units can decompress the same payload repeatedly. HeifContext::interpret_heif_file_images() processes multiple compressed metadata items during file opening, allowing a small file to consume unbounded memory and terminate the process. This issue is fixed in version 1.23.2.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Handling of Highly Compressed Data (Data Amplification)

The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

More Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities (CWE-409)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).

References

Other vulnerabilities in libheif

All libheif vulnerabilities

Recent Improper Handling of Highly Compressed Data (Data Amplification) vulnerabilities

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