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Fencer Intel
medium 4.4

CVE-2026-80490 json

Algorithm::AhoCorasick::XS versions through 0.04 for Perl read the haystack string length before the scalar is stringified

published last mo. modified 2d ago also EUVD-2026-90025

cvss
4.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

Algorithm::AhoCorasick::XS versions through 0.04 for Perl read the haystack string length before the scalar is stringified.

The matches, first_match and match_details methods use the T_STD_STRING typemap to translate Perl scalars (SVs) into strings via the std::string constructor, using the SvPV macro to stringify the haystack input, and the SvCUR macro to determine the length of the SV.

When the input SVs are references, integers (IVs) or floats (NVs), the SvCUR macro will return an invalid length if it is run before the input is stringified, leading to an out-of-bounds read which can abort the process.

Note that the evaluation order of arguments to std::string is unspecified. Depending on the compiler, SvCUR may be run first and lead to an abort that cannot be caught within Perl.

This can be triggered when the haystack is a numeric value, for example,

my $ac = Algorithm::AhoCorasick::XS->new( [ "11", "22" ] ); $ac->matches( 211 );

This can occur when the haystack is the result of reading data from decoded JSON or a numeric database column. It can also be triggered when using a blessed object as a haystack.

Patch / fix

Is CVE-2026-80490 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CISA ADP 3.1 4.4 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
CNA 3.1 4.4 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L

Affected products

  • cpan Algorithm-AhoCorasick-XS

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.