Apple Safari 26.4: Sandbox Escape via Memory Handling
CVE-2026-28859 Published on March 25, 2026
The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, tvOS 26.4, visionOS 26.4, watchOS 26.4. A malicious website may be able to process restricted web content outside the sandbox.
Vulnerability Analysis
CVE-2026-28859 can be exploited with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Types
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-28859 has been classified to as a Dangling pointer vulnerability or weakness.
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur 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. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-28859 has been classified to as a Memory Corruption vulnerability or weakness.
What is a Classic Buffer Overflow Vulnerability?
The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. A buffer overflow condition exists when a program attempts to put more data in a buffer than it can hold, or when a program attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the program copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.
CVE-2026-28859 has been classified to as a Classic Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-28859
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Affected Versions
Apple Safari:- Before 26.4 is affected.
- Before 26.4 is affected.
- Before 26.4 is affected.
- Before 26.4 is affected.
- Before 26.4 is affected.
- Before 26.4 is affected.
- Version 0:2.52.3-1.el7_9 and below * is unaffected.
- Version 0:2.52.3-1.el8_10 and below * is unaffected.
- Version 0:2.52.3-1.el8_4 and below * is unaffected.
- Version 0:2.52.3-1.el8_4 and below * is unaffected.
- Version 0:2.52.3-1.el8_6 and below * is unaffected.
- Version 0:2.52.3-1.el8_6 and below * is unaffected.
- Version 0:2.52.3-1.el8_6 and below * is unaffected.
- Version 0:2.52.3-1.el8_8 and below * is unaffected.
- Version 0:2.52.3-1.el8_8 and below * is unaffected.
- Version 0:2.52.3-0.el9_7.1 and below * is unaffected.
- Version 0:2.52.3-1.el9_8 and below * is unaffected.
- Version 0:2.52.3-1.el9_0 and below * is unaffected.
- Version 0:2.52.3-1.el9_2 and below * is unaffected.
- Version 0:2.52.3-1.el9_4 and below * is unaffected.
- Version 0:2.52.3-1.el9_6 and below * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.