CVE-2026-110688: high-severity vulnerability in Cpanel-JSON-XS
Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use by revalidating the remaining buffer per value in incr_parse
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.5%
Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use by revalidating the remaining buffer per value in incr_parse.
At the first non-ASCII byte in a string, the decoder validates UTF-8 from there to the end of its input. incr_parse decodes each buffered value with a fresh decoder, so every value revalidates the rest of the buffer, and doubling the input quadruples the work.
A peer that sends about a megabyte of ordinary non-ASCII JSON in one read ties up the process for seconds of CPU time.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Cpanel-JSON-XSRelated CVEs — Cpanel-JSON-XS
In the same product, most dangerous first.
CVE-2026-110674MEDIUMCpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hvEPSS 0.5%CVE-2026-110685CRITICALCpanel::JSON::XS versions before 4.80 for Perl leak the decoded arguments of a tagged value when its THAW method dies in decode_tagEPSS 0.5%CVE-2026-110678HIGHCpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by buffering incremental input past max_size in incr_parseEPSS 0.5%CVE-2026-110676HIGHCpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignumEPSS 0.5%CVE-2026-110673HIGHCpanel::JSON::XS versions before 4.80 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tagEPSS 0.5%CVE-2026-110672HIGHCpanel::JSON::XS versions before 4.80 for Perl leak the decoded key of an object rejected for a duplicate key or a missing colon in decode_hvEPSS 0.5%