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Response snapshot Oct 31, 2026, 01:26 UTC

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VulnerabilityGHSA-hff9-5pqw-6w9f

imgproxy has integer overflow in imgproxy ICO loader that causes denial of service and may permit remote code execution

The ICO loader allocates data_size + BMP_FILE_HEADER_LEN bytes after reading a 32-bit attacker-controlled data_size. For data_size > UINT32_MAX - BMP_FILE_HEADER_LEN, the addition wraps before allocation.

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: github.com/imgproxy/imgproxy/v3: 4.0.16; github.com/imgproxy/imgproxy/v2: 4.0.16; github.com/imgproxy/imgproxy: 4.0.16. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-hff9-5pqw-6w9f (opens a new tab)

What happened

Summary

The ICO loader allocates data_size + BMP_FILE_HEADER_LEN bytes after reading a 32-bit attacker-controlled data_size. For data_size > UINT32_MAX - BMP_FILE_HEADER_LEN, the addition wraps before allocation. imgproxy then writes the ICO prefix and reads up to the original declared size starting 14 bytes into the undersized allocation. A network client can turn this heap overflow into remote denial of service or remote code execution.

Technical details

The vulnerable path is in [vips/icoload.c at commit f4fedbb](https://github.com/imgproxy/imgproxy/blob/f4fedbb5c7f6684e7a8e0a9bb7e666773f3c40c0/vips/icoload.c#L154-L164):

Continue reading
uint32_t data_size = GUINT32_FROM_LE(largest_image_header.data_size);

VipsPel *data = (VipsPel *) VIPS_MALLOC(NULL, data_size + BMP_FILE_HEADER_LEN);
void *actual_data = data + BMP_FILE_HEADER_LEN;

if (vips_foreign_load_read_full(ico->source, actual_data, data_size) <= 0) {
 vips_error("vips_foreign_load_ico_header", "unable to read ICO image data from the source");
 return -1;
}

The crafted directory entry contains:

data_size = 0xfffffff5 (4294967285)
data_offset = 22
BMP header size = 14
32-bit result = (0xfffffff5 + 14) mod 2^32 = 3

The allocation is therefore three bytes. actual_data points 14 bytes after the allocation base. The fixture contains 64 bytes after the ICO header, so the source callback copies those 64 bytes to an invalid destination before it can report that the declared multi-gigabyte payload is incomplete.

The complete source-to-sink path is:

1. Attacker-controlled bytes begin with the ICO magic 00 00 01 00. 2. imgproxy identifies the source as ICO and dispatches it to vips_icoload_source_go. 3. vips_foreign_load_ico_header reads the attacker-controlled data_size. 4. The 32-bit addition wraps, and VIPS_MALLOC receives the value three. 5. vips_foreign_load_read_full passes the original data_size to the Go source callback. 6.

The callback writes the available source bytes through the invalid pointer, corrupting the process heap.

Impact

A crafted image can terminate the imgproxy process handling it or potentially lead to remote code execution due to heap corruption.

Affected package ranges reported by GitHub: github.com/imgproxy/imgproxy/v3: >= 4.0.0, < 4.0.16 github.com/imgproxy/imgproxy/v2: >= 4.0.0, < 4.0.16 github.com/imgproxy/imgproxy: >= 4.0.0, < 4.0.16

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-hff9-5pqw-6w9f (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-hff9-5pqw-6w9f, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). imgproxy has integer overflow in imgproxy ICO loader that causes denial of service and may permit remote code execution. https://kevwire.com/record/GHSA-hff9-5pqw-6w9f

MLA

"imgproxy has integer overflow in imgproxy ICO loader that causes denial of service and may permit remote code execution." KEVWire, 30 Oct. 2026, kevwire.com/record/GHSA-hff9-5pqw-6w9f.

Chicago

KEVWire. "imgproxy has integer overflow in imgproxy ICO loader that causes denial of service and may permit remote code execution." Last modified October 30, 2026. https://kevwire.com/record/GHSA-hff9-5pqw-6w9f.

Evidence summary (plain text)

imgproxy has integer overflow in imgproxy ICO loader that causes denial of service and may permit remote code execution (Oct 30, 2026).
The ICO loader allocates data_size + BMP_FILE_HEADER_LEN bytes after reading a 32-bit attacker-controlled data_size. For data_size > UINT32_MAX - BMP_FILE_HEADER_LEN, the addition wraps before allocation. imgproxy then writes the ICO prefix and reads up to the original declared size starting 14 bytes into the undersized allocation. A network client can turn this heap overflow into remote denial of service or remote code execution.
Sources:
GitHub-reviewed advisory GHSA-hff9-5pqw-6w9f: https://github.com/advisories/GHSA-hff9-5pqw-6w9f
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: GHSA-hff9-5pqw-6w9f.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 31, 2026, 00:50 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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