High 7.5Published Sep 28, 2026

CVE-2026-85644XS::Parse::Infix versions from 0.40 through 0.49 for Perl treat a number as an array reference

Updated under an hour ago (2026-10-19 07:23 UTC)

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EPSS puts the chance of exploitation in the next 30 days at 0.39%, higher than 31% of scored CVEs.

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Exploited in the last 30 days

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: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-843, CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.39% (percentile 31)
Assigned by: CPANSec
NVD analysis: Deferred
Record last updated: Sep 30, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

No affected products are listed yet.

References

https://metacpan.org/release/PEVANS/XS-Parse-Keyword-0.50/changesrelease-notes
https://metacpan.org/release/PEVANS/XS-Parse-Keyword-0.50/diff/PEVANS/XS-Parse-Keyword-0.49#src/infix.c
http://www.openwall.com/lists/oss-security/2026/09/28/14

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