SB2026110370 - Fedora 45 update for python-pillow
Published: November 3, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Heap-based buffer overflow (CVE-ID: CVE-2026-112393)
CWE-ID: CWE-122 - Heap-based Buffer Overflow
CVSSv4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service and potentially execute arbitrary code.
The vulnerability exists due to a heap-based buffer overflow in Pillow's _tiffWriteProc function in src/libImaging/TiffDecode.c when saving a TIFF image through libtiff to a destination without a usable file descriptor, such as io.BytesIO. A remote attacker can supply a crafted single-band TIFF with an attacker-controlled out-of-line tag value to a service that opens and re-saves the image to trigger an undersized allocation and overwrite adjacent heap memory, causing a process crash or potentially executing arbitrary code.
The reported code-execution chain additionally requires addresses disclosed by a separate vulnerability.
2) Improper handling of highly compressed data (CVE-ID: CVE-2026-112892)
CWE-ID: CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service through memory exhaustion.
The vulnerability exists due to uncontrolled expansion of run-length encoded data in Pillow's MSP RLE decoder when loading image pixels. A remote attacker can supply a small crafted MSP image that expands into an unbounded io.BytesIO buffer without a limit tied to the declared image size to exhaust application memory and cause a denial of service.
Remediation
Install update from vendor's website.