Critical Memory‑Corruption Flaw in XML::Parser for Perl Patched as CVE‑2006‑10002
A long‑known but only recently formalized vulnerability in the Perl module XML::Parser has been assigned CVE‑2006‑10002, exposing users of older versions to memory‑corruption and potential remote‑code‑execution risks when parsing malicious XML content.
CVE‑2006‑10002 affects XML::Parser versions up to 2.47 for Perl. The flaw lies in the parse_stream() function inside Expat.xs When the input stream is wrapped with a :utf8 PerlIO layer.
In this configuration, Perl read() returns decoded Unicode characters, whereas SvPV() it returns the corresponding multi‑byte UTF‑8 byte sequences.
When the XML parser’s pre‑allocated input buffer is filled with these longer UTF‑8 byte groups, the buffer size can be exceeded, triggering a heap‑based buffer overflow. This can lead to heap corruption (including double‑free‑like conditions) and process crashes, with the potential for more severe exploitation if controllable memory layouts are achievable.
The vulnerability is formally categorized under CWE‑122 (Heap‑based Buffer Overflow) and CWE‑176 (Improper Handling of Unicode Encoding), reflecting both the buffer‑management bug and the UTF‑8 handling logic error.
Because XML::Parser is commonly embedded in Perl web‑facing services, log‑processing tools, and other XML‑driven automation, unpatched instances can be exposed to remotely‑triggered crashes or memory‑corruption bugs driven by crafted XML bodies or file uploads.
The CVSS 3.1 base score of 9.8 (CRITICAL) is assigned by a third‑party source, reflecting an Attack Vector: Network (AV:N), Attack Complexity: Low (AC:L), No Privileges Required (PR:N), and No user interaction (UI:N), with High impact on confidentiality, integrity, and availability (C:H/I:H/A:H). NIST registers a more conservative CVSS 3.1 7.5 (HIGH) focusing only on availability impact (A:H), while Red Hat notes a 6.5 (MEDIUM) where a user interaction requirement is presumed.
The EPSS score of 0.06% suggests relatively low projected exploitation probability over the next 30 days, consistent with the fact that a patch has been publicly available since 2006‑06‑13, even though the CVE was only formalized in 2026.
The vulnerability primarily affects XML::Parser (distribution by Todd Rinaldo, “Toddr”) for Perl, with all versions before 2.48 considered vulnerable. The CPAN‑centric CPE identifier is:
cpe:2.3:a:toddr:xml\:\:parser:*:*:*:*:*:perl:*:*
Any application or framework that depends on XML::Parser 2.47 or earlier, such as Perl‑based web services, content‑management tools, or XML‑enabled middleware stacks, should be treated as potentially exposed if XML input is not strictly controlled, pre‑parsed, or validated.
Remediation and mitigation
The CPAN Security Group and project maintainers recommend three parallel actions for affected environments:
- Upgrade XML::Parser to version 2.48 or later once released, which incorporates a fix for the UTF‑8 buffer‑overflow path in
parse_stream(). - Apply the historic patch that has been publicly available since 2006‑06‑13, referenced in the Request Tracker ticket and GitHub issue/commit:
- RT Ticket:
https://rt.cpan.org/Ticket/Display.html?id=19859 - GitHub issue:
https://github.com/cpan-authors/XML-Parser/issues/64 - Patch commit:
https://github.com/cpan-authors/XML-Parser/commit/6b291f4d260fc124a6ec80382b87a918f372bc6b.patch
- RT Ticket:
- Where immediate patching or upgrade is not feasible, enforce strict input validation, reject untrusted XML payloads, and limit XML‑parsing privileges (e.g., run parsing in isolated containers or sandboxes) to reduce blast radius.
Organizations running legacy Perl stacks should inventory XML‑parsing modules and XML::Parser dependencies, then prioritize remediation for any systems reachable over the network or that process user‑provided XML.
Site: cybersecuritypath.com
Reference:
About the Author
