CVE-2026-85644
Received
Received - Intake
XS::Parse::Infix Perl Array Reference Validation Bypass
Vulnerability report for CVE-2026-85644, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-28
Last updated on: 2026-09-28
Assigner: CPANSec
Description
Description
XS::Parse::Infix versions from 0.40 through 0.49 for Perl treat a number as an array reference.
The wrapper function XS::Parse::Infix generates for a list-associative infix operator checks whether arguments are array references, but it tests using SvRV() rather than SvROK(). SvRV() reads a union slot that only holds a referent once SvROK(sv) is true, so the guard never validates that it is a reference. For an IV or NV that slot holds the number itself, SvRV() returns the caller's value and SvTYPE() dereferences it at offset 12. This will generally result in a segmentation fault.
An application that hands the wrapper a list built from decoded input (for example, from JSON) lets whoever supplies a number in that list choose the address that the interpreter dereferences.
An ordinary string's byte 12 is rarely SVt_PVAV so the guard croaks by luck, but an attacker-crafted string carrying 0x0b there passes, and the buffer is then used as an AV head, with AvARRAY taken from bytes 16-23 and its entries pushed onto the Perl stack as live SVs.
A simple proof-of-concept uses the zip operator:
use Syntax::Operator::Zip 'zip';
my @args = ([1], 2);
zip(@args);
CVSS Scores
EPSS Scores
| Probability: | |
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Meta Information
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-843 | The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. |
| CWE-125 | The product reads data past the end, or before the beginning, of the intended buffer. |
