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);
References
Configurations
No configuration.
History
30 Sep 2026, 20:17
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.5 |
28 Sep 2026, 19:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
28 Sep 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-28 17:17
Updated : 2026-09-30 20:17
NVD link : CVE-2026-85644
Mitre link : CVE-2026-85644
CVE.ORG link : CVE-2026-85644
JSON object : View
Products Affected
No product.