Vulnerability · Published Jun 4, 2026 · Assigned by CPANSec
CVE-2026-8829HTML::Entities versions before 3.84 for Perl read freed heap memory in _decode_entities
High 7.5
In plain English
A high-severity use-after-free in HTML::Entities from OALDERS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
HTML::Entities versions before 3.84 for Perl read freed heap memory in _decode_entities. The XS routine backing HTML::Entities::_decode_entities cached a pointer (repl) into the entity-value SV returned by hv_fetch on the entity2char hash. When the input SV was identical to a value SV in that hash, and that value contained its own key as an entity reference, a later call to grow_gap() reallocated the SV's PV buffer and freed the backing allocation that repl still pointed into. The subsequent copy loop read repl_len bytes from the freed allocation. The read may disclose adjacent heap contents into the destination SV.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libhtml-parser-perl | 3.81-1+deb12u1 | DEBIAN-CVE-2026-8829 |
| Debian:13 | libhtml-parser-perl | 3.83-2~deb13u1 | DEBIAN-CVE-2026-8829 |
| Debian:14 | libhtml-parser-perl | 3.83-2 | DEBIAN-CVE-2026-8829 |
| Ubuntu:22.04:LTS | libhtml-parser-perl | 3.76-1ubuntu0.1 | UBUNTU-CVE-2026-8829 |
| Ubuntu:22.04:LTS | libhtml-parser-perl | 3.76-1ubuntu0.1 | USN-8587-1 |
| Ubuntu:24.04:LTS | libhtml-parser-perl | 3.81-1ubuntu0.1 | USN-8587-1 |
| Ubuntu:24.04:LTS | libhtml-parser-perl | 3.81-1ubuntu0.1 | UBUNTU-CVE-2026-8829 |
| Ubuntu:25.10 | libhtml-parser-perl | no fix listed | UBUNTU-CVE-2026-8829 |
| Ubuntu:26.04:LTS | libhtml-parser-perl | 3.83-1ubuntu0.1 | USN-8587-1 |
| Ubuntu:26.04:LTS | libhtml-parser-perl | 3.83-1ubuntu0.1 | UBUNTU-CVE-2026-8829 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| OALDERS | HTML::Entities | 0 – before 3.84 |
Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N