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);

The remote Ubuntu 26.04 LTS / 26.10 host has a package installed that is affected by a vulnerability as referenced in the USN-8940-1 advisory.

    It was discovered that the Perl XS::Parse::Keyword module did not correctly handle certain inputs. If a     user or automated system were tricked into receiving specially crafted input, an attacker could cause a     denial of service.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has a package installed that is affected by a vulnerability as referenced in the openSUSE- SU-2026:22101-1 advisory.

    This update for perl-XS-Parse-Keyword fixes the following issue:

    - CVE-2026-85644: number treated as an array reference in `infix.c` (bsc#1283247).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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); (CVE-2026-85644)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
369328	Ubuntu 26.04 LTS / 26.10 : Perl XS::Parse::Keyword module vulnerability (USN-8940-1)	Nessus	Ubuntu Local Security Checks	Local	high
367231	openSUSE 16 Security Update : perl-XS-Parse-Keyword (openSUSE-SU-2026:22101-1)	Nessus	SuSE Local Security Checks	Local	high
351097	Linux Distros Unpatched Vulnerability : CVE-2026-85644	Nessus	Misc.	Local	high

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