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CVE-2026-59087 is a heap buffer overflow vulnerability discovered in the GIMP image manipulation program, specifically within its Seattle Filmworks (.sfw) file loader plugin. The flaw resides in the `file-seattle-filmworks.c` source file at line 323, and it affects GIMP version 3.2.4 as well as all prior versions. The root cause is an unsafe memory allocation and subsequent `fread` operation that does not properly validate attacker-controlled length values.
When the Seattle Filmworks loader processes a crafted `.sfw` file, it reads two values derived from the file’s content: `index` and metadata_len
</code>. The loader uses only `metadata_len[bash]` to allocate a small buffer for `photo_date` via <code>g_malloc(metadata_len[bash] + 1)</code>. However, the subsequent `fread` call reads `index - metadata_len[bash]` bytes into this buffer, without checking that this read size does not exceed the allocated memory. Both `index` and `metadata_len[bash]` are attacker-controlled and independent of each other. By setting `index` to a value significantly larger than <code>metadata_len[bash]</code>, an attacker can cause the `fread` to write several kilobytes of controlled data beyond the heap buffer's intended boundary.
In a build compiled with `_FORTIFY_SOURCE` (the default on Ubuntu systems), glibc detects the overflow at runtime and aborts the program, resulting in a denial of service. However, in a non-FORTIFY build, the memory corruption occurs silently, potentially allowing an attacker to overwrite adjacent heap metadata or other critical data structures. This corruption can lead to arbitrary code execution within the context of the GIMP application, or a denial of service through a crash. The vulnerability is classified under CWE-787 (Out-of-bounds Write). Exploitation requires user interaction, as the victim must be tricked into opening a specially crafted Seattle Filmworks file. The CVSS v3.1 base score is 7.8 (High), with the vector string <code>AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H</code>.
<h2 style="color: blue;">DailyCVE Form:</h2>
Platform: GIMP 3.2.4
Version: ≤ 3.2.4
Vulnerability: Heap buffer overflow
Severity: High (7.8)
Date: August 10, 2026
<h2 style="color: blue;">Prediction: Q4 2026</h2>
<h2 style="color: blue;">What Undercode Say:</h2>
The heap overflow is triggered by the discrepancy between the allocated buffer size and the `fread` read length in <code>file-seattle-filmworks.c</code>. The following bash commands can be used to test for the vulnerability in a GIMP installation:
[bash]
Check GIMP version
gimp --version
On Debian/Ubuntu, check if _FORTIFY_SOURCE is enabled
getconf GNU_LIBC_VERSION
ldd --version | head -1
Reproduce with a crafted .sfw file (PoC available)
The following Python snippet generates a minimal proof-of-concept file
python3 -c "
header = bytearray(0xE0)
header[0:6] = b'SFW94A'
data = bytearray()
data += b'A' 5
data += b' '
data += b'B' 4
data += b' '
data += b'C' 9900
data += b'\x00'
with open('poc_sfw.sfw', 'wb') as f:
f.write(header + data)
"
Opening 'poc_sfw.sfw' in GIMP will trigger the overflow
Exploit: (Educational Purposes!)
A remote attacker can craft a malicious Seattle Filmworks file with the following structure:
- 0x00–0x05: Magic bytes `"SFW94A"` – required to enter the vulnerable code branch.
- 0x06–0xDF: Header padding (zeros).
- 0xE0–0xE4: Five bytes before the first space – sets metadata_len[bash] = 5.
- 0xE5: First space (0x20) – delimiter.
- 0xE6–0xE9: Four bytes – sets metadata_len[bash] = 10.
- 0xEA: Second space (0x20) – delimiter.
- 0xEB–0x2796: 9,900 bytes of filler (e.g., `'C'` characters) – no NUL, no spaces.
- 0x2797: NUL terminator (0x00) – loop exits with index = 9911.
The buggy `fread` then reads `9911 - 10 = 9901` bytes into the 11-byte `photo_date` buffer, overflowing the heap.
Protection:
- Avoid opening Seattle Filmworks (.sfw) files from untrusted sources.
- Apply vendor patches as soon as they become available. As of August 2026, no fixed version has been released for Debian distributions. Red Hat has rated the issue as Important and is expected to release errata updates.
- Compile GIMP with `_FORTIFY_SOURCE` – this causes glibc to abort on overflow detection, turning potential code execution into a denial of service.
- Disable or remove the Seattle Filmworks plugin (
file-sfw) if not required.
Impact:
Successful exploitation allows an attacker to write several kilobytes of controlled data beyond the heap buffer. This can result in memory corruption, potentially leading to arbitrary code execution with the privileges of the GIMP process, or a denial of service through application crash. The vulnerability affects all GIMP versions up to 3.2.4 across multiple platforms, including Red Hat Enterprise Linux 6, 7, 8, and 9. Due to the low attack complexity and no required privileges, this flaw poses a significant risk to users who process untrusted image files.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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