imgproxy has unbounded memory allocation in ICO loader that allows unauthenticated memory-exhaustion DoS via crafted data_size field

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary Unbounded and unvalidated memory allocation in imgproxy's ICO loader (`vips/icoload.c`). An attacker-controlled `data_size` field (u32) from the ICO directory entry is passed directly to `VIPS_MALLOC` without any bounds check, so a single crafted 23-byte ICO file makes an imgproxy worker attempt a ~4GB allocation. Present in the latest release (v4.0.15) and the 3.3.x series; confirmed on a live production deployment of imgproxy v4.0.15.

Details In `vips_foreign_load_ico_header` in `vips/icoload.c`, the selected directory entry's `data_size` is read and used directly for the allocation: ``` uint32_t data_size = GUINT32_FROM_LE(largest_image_header.data_size); // BMP file explicitly excludes BITMAPFILEHEADER, so we need to add it manually. VipsPel *data = (VipsPel *) VIPS_MALLOC(NULL, data_size + BMP_FILE_HEADER_LEN); ``` There is no validation that `data_size` is sane nor any check that the file actually contains `data_size` bytes at the declared `data_offset`. A…

Published by the source

30 Oct 2026, 22:55 UTC

Last modified by the source

30 Oct 2026, 23:15 UTC

Source last checked

31 Oct 2026, 06:45 UTC

1. Revision 2 · amended · 31 Oct 2026

   Amended from osv record GHSA-mmq5-xm89-9pfg

2. Revision 1 · created · 30 Oct 2026

   Published from ghsa record GHSA-mmq5-xm89-9pfg

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-mmq5-xm89-9pfg

Advisory: imgproxy has unbounded memory allocation in ICO loader that allows unauthenticated memory-exhaustion DoS via crafted data_size field
IDs: GHSA-mmq5-xm89-9pfg
Record: https://patchnext.com/advisories/ghsa-mmq5-xm89-9pfg (revision 2, source checked 31 Oct 2026, 06:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/imgproxy/imgproxy/v3 4.0.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/imgproxy/imgproxy/v3: affected >= 3.3.0, < 4.0.16; fixed in 4.0.16

## Suggested inspection (read-only)
- Go github.com/imgproxy/imgproxy/v3: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/imgproxy/imgproxy/v3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mmq5-xm89-9pfg (GitHub-reviewed advisory GHSA-mmq5-xm89-9pfg lists affected ranges: Go github.com/imgproxy/imgproxy/v3 >=3.3.0 <=4.0.15)
- Verified: https://osv.dev/vulnerability/GHSA-mmq5-xm89-9pfg (OSV record GHSA-mmq5-xm89-9pfg lists affected ranges: Go github.com/imgproxy/imgproxy/v3 >=3.3.0 <4.0.16 (fixed))

Commands are suggestions: review each one before running it.