Description
Cpanel::JSON::XS versions from 4.20 before 4.80 for Perl write out of bounds when a tied or shared hash grows during canonical encoding in encode_hv.
With canonical, the keys of a tied or threads::shared hash are counted before a second pass collects them for sorting. The encoder uses a fixed 64-entry stack array or, for larger counts, a heap array sized from the first pass. If the second pass exceeds that capacity, entries are written out of bounds before the counts are compared.
This corrupts stack or heap memory and can crash the process.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Cpanel-JSON-XS | 4.20 – < 4.80 | 4.80 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libcpanel-json-xs-perl | 4.80-1 | — |
| Debian 13 | libcpanel-json-xs-perl | No fix yet | — |
| Debian 12 | libcpanel-json-xs-perl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 26.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 24.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 22.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | perl-Cpanel-JSON-XS | 4.800.0-150700.3.9.1 | SUSE-SU-2026:4926-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | perl-Cpanel-JSON-XS | 4.800.0-1.1 | openSUSE-SU-2026:12217-1 |
| openSUSE Leap 16.0 | perl-Cpanel-JSON-XS | 4.800.0-bp160.1.1 | openSUSE-SU-2026:22187-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | perl-Cpanel-JSON-XS | 4.25-2.amzn2023.0.10 | ALAS2023-2026-3352 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | perl-Cpanel-JSON-XS | No fix yet | — |
Advisories 4
- ALAS2023-2026-3352 Important: perl-Cpanel-JSON-XS security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 2, 2026
- openSUSE-SU-2026:22187-1 Security update for perl-Cpanel-JSON-XS SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:4926-1 Security update for perl-Cpanel-JSON-XS SUSE / openSUSE Security Updates · Oct 29, 2026
- openSUSE-SU-2026:12217-1 perl-Cpanel-JSON-XS-4.800.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 22, 2026