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HighVulnerabilityGHSA-mmq5-xm89-9pfgupdated 30 Oct 2026, 22:56 UTC

imgproxy can be made to grab about 4GB of memory from one tiny crafted icon file

A specially crafted tiny icon file can make imgproxy try to reserve about 4GB of memory. Repeated requests can crash the service or slow down the server.

Fixed in 4.0.16 · out Official source
SeverityHighCVSS 7.5 of 10
Being exploited?UnclearNo reports either way yet
Fix available?Yes4.0.16 · since 30 Oct 2026
How sure is this?Official sourceBacked by an official source

How the attack works simplified

  1. 1Attacker sends fileCrafted 23-byte ICO file
  2. 2imgproxy parses ICOReads declared data_size value
  3. 3Huge allocationAbout 4GB requested with no bounds check
  4. 4Memory exhaustedWorker crashes or host slows
  5. ResultRepeatable memory exhaustion and denial of service

What happened

An unbounded, unvalidated memory allocation in imgproxy's ICO loader (vips/icoload.c) uses an attacker-controlled data_size value from the ICO directory entry directly in VIPS_MALLOC without any bounds check.

Why it is dangerous: An unauthenticated attacker can send a 23-byte ICO file to trigger roughly 4GB allocations per request, causing memory exhaustion, worker crashes, or denial of service on any imgproxy deployment that processes attacker-supplied images.

Are you affected?

You are affected if you run imgproxy v3.3.0 through v4.0.15 and it processes images from untrusted sources.

Package / productAffected versionsFixed in
github.com/imgproxy/imgproxy/v3 · go>= 3.3.0, <= 4.0.154.0.16

What to do

  1. Update imgproxy to version 4.0.16 or later
  2. If you cannot update right away, disable local file sources (IMGPROXY_ENABLE_LOCAL_FILES) and restrict which image sources imgproxy accepts
  3. Set memory limits on imgproxy workers or containers so a single request cannot exhaust the host

Timeline

  1. 30 Oct 2026, 22:55 UTC
    Publicly disclosed
  2. 30 Oct 2026, 22:55 UTC
    Reported by GitHub Advisory · GitHub Advisory
  3. 30 Oct 2026, 22:56 UTC
    Picked up by Zero Radar

Sources 1 report, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
GHSA-mmq5-xm89-9pfg
CVSS
7.5 / 10
Disclosed
30 Oct 2026, 22:55 UTC
On Zero Radar
30 Oct 2026, 22:56 UTC (0 min after disclosure)
Last change
30 Oct 2026, 22:56 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

imgproxy can be made to grab about 4GB of memory from one tiny crafted icon file · Zero Radar