Bug 2556460

Summary:	CVE-2026-110676 perl-Cpanel-JSON-XS: Memory and CPU exhaustion via allow_bignum exponent encoding [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	perl-Cpanel-JSON-XS	Assignee:	Paul Howarth <paul>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	paul, perl-devel
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["38bedbe8-b37a-4e19-bd95-f891026cc87e"]}
Fixed In Version:	perl-Cpanel-JSON-XS-4.80-1.fc43 perl-Cpanel-JSON-XS-4.80-1.fc44 perl-Cpanel-JSON-XS-4.80-1.fc45	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-24 16:16:40 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2555753

Description Guilherme de Almeida Suckevicz 2026-10-20 20:47:05 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum.

With allow_bignum, a JSON number with a fraction or exponent decodes to a Math::BigFloat, which stores the exponent separately and so decodes cheaply. Encoding it untyped or as JSON_TYPE_FLOAT writes the plain decimal form with one digit per unit of exponent. Nothing bounds the exponent, so the 12-byte text [1e30000000] encodes to 30 MB.

Untrusted JSON decoded with allow_bignum and encoded again can exhaust memory and CPU.

Comment 1 Fedora Update System 2026-10-21 09:12:47 UTC

FEDORA-2026-ad8dfeadc9 (perl-Cpanel-JSON-XS-4.80-1.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ad8dfeadc9

Comment 2 Fedora Update System 2026-10-21 09:15:33 UTC

FEDORA-2026-3ab4727120 (perl-Cpanel-JSON-XS-4.80-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-3ab4727120

Comment 3 Fedora Update System 2026-10-21 09:18:16 UTC

FEDORA-2026-4447e52d23 (perl-Cpanel-JSON-XS-4.80-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-4447e52d23

Comment 4 Fedora Update System 2026-10-24 16:16:40 UTC

FEDORA-2026-4447e52d23 (perl-Cpanel-JSON-XS-4.80-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 5 Fedora Update System 2026-10-24 16:36:24 UTC

FEDORA-2026-3ab4727120 (perl-Cpanel-JSON-XS-4.80-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 6 Fedora Update System 2026-10-31 18:42:21 UTC

FEDORA-2026-ad8dfeadc9 (perl-Cpanel-JSON-XS-4.80-1.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.