View at Official ubuntu advisory, NVD, CVE.org · CVE detail
Freshness: upstream tracker timestamp is available; use API updated time as primary recency signal.
CVE-2010-4657 negligible priority: Ubuntu including 1 source packages (php5), 15 status rows across 15 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, trusty, upstream, utopic, vivid, wily, xenial): not-affected 7, ignored 6, DNE 1, needs-triage 1.
PHP5 before 5.4.4 allows passing invalid utf-8 strings via the xmlTextWriterWriteAttribute, which are then misparsed by libxml2. This results in memory leak into the resulting output.