PHP HTTP Stream Wrapper Redirect OOB Byte Exploit
CVE-2026-93682 Published on September 25, 2026
Out-of-bounds read in the HTTP stream wrapper when following a redirect with an empty Location header
When the HTTP stream wrapper follows a redirect and the response carries a Location header with an empty value, the redirect code reads one byte past the end of the heap buffer holding the location. The value of that out-of-bounds byte decides which redirect target is built, so a malicious server controls whether the client is sent to the host root or to the current directory.
Vulnerability Analysis
CVE-2026-93682 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
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.
Products Associated with CVE-2026-93682
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Affected Versions
PHP Group PHP:- Version 8.2.* and below 8.2.34 is affected.
- Version 8.3.* and below 8.3.35 is affected.
- Version 8.4.* and below 8.4.26 is affected.
- Version 8.5.* and below 8.5.11 is affected.