CVE-2026-34757
Description
A flaw was found in libpng, a library used for handling PNG (Portable Network Graphics) image files. This vulnerability arises when an application reuses a pointer, previously obtained from functions like png_get_PLTE, by passing it back to a corresponding setter function within the same image structure. This action causes the setter to access memory that has already been deallocated, leading to a use-after-free condition. A local attacker could potentially exploit this flaw to corrupt image metadata or disclose sensitive information from the application's memory.
Statement
There's a use-after-free vulnerability in libpng. The flaw occurs when an application reuses a pointer from png_get_PLTE, png_get_tRNS, or png_get_hIST and passes it to a corresponding setter, leading to memory corruption or information disclosure. A local attacker could exploit this if a vulnerable application processes PNG files in this specific manner.
Red Hat Product Security team has rated this as having a moderate impact as the user needs to be tricked to open the maliciously crafted PNG image, additionally the attacker doesn't have full control if the content it's exfiltrating or corruption in the memory.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | 4.4 | 5.1 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | Low | Low |
| Integrity Impact | Low | Low | Low |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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