CVE-2026-85644

NameCVE-2026-85644
DescriptionXS::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);
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1149243

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libxs-parse-keyword-perl (PTS)bookworm0.33-1fixed
trixie0.48-2vulnerable
forky, sid0.51-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libxs-parse-keyword-perlsourcebookworm(not affected)
libxs-parse-keyword-perlsource(unstable)0.51-11149243

Notes

[trixie] - libxs-parse-keyword-perl <no-dsa> (Minor issue)
[bookworm] - libxs-parse-keyword-perl <not-affected> (Vulnerable code introduced in 0.40)
https://lists.security.metacpan.org/cve-announce/msg/43916020/
https://metacpan.org/release/PEVANS/XS-Parse-Keyword-0.50/diff/PEVANS/XS-Parse-Keyword-0.49/src/infix.c

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