Description
Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl accept malformed UTF-8 in bare hash keys under allow_barekey in decode_hv.
With utf8 and allow_barekey, which relaxed enables, a quoted key is validated as UTF-8 but a bare key's bytes are stored as a UTF-8 flagged string without any check. Malformed UTF-8, control bytes and backslashes reach the decoded hash, while malformed UTF-8 and control bytes in a quoted key or a value are rejected.
Later operations on the key, including lc, uc or encoding the hash again, die with a malformed UTF-8 error.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Cpanel-JSON-XS | 4.33 – < 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 | — |
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 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | perl-Cpanel-JSON-XS | No fix yet | — |
Advisories 3
- 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