CVE-2026-16768
Description
A flaw was found in gdk-pixbuf. When parsing a specially crafted ICO file with pixel values that exceed the defined palette range, an out-of-bounds read can occur due to improper bounds checking against the actual palette size. This vulnerability causes heap bytes to be interpreted as valid palette indices and rendered as RGB pixel values in the output image, allowing an attacker to extract heap content via the generated output, such as a thumbnail.
Statement
To exploit this flaw, an attacker must be able to process a specially crafted ICO file with an application linked to the gdk-pixbuf library. The only security impact of this issue is an information leak of memory contents via the generated output, such as a thumbnail. Also, the attacker does not have full control of the information obtained, further limiting its impact. Due to these reasons, this vulnerability has been rated with a moderate severity.
Mitigation
To mitigate this vulnerability, if the application does not require support for ICO files, disable the gdk-pixbuf ICO loader to prevent the vulnerable module from being executed.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
Acknowledgements
Red Hat would like to thank Matej Smycka for reporting this issue.
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