As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DESCENDING THRU FL 260 WHILE IN THE CLOUDS CREW SMELLED THAT DIRTY SOCK SMELL. MAINTENANCE ACCOMPLISHED SMOKE ODOR FUME TROUBLESHOOTING TASK CARD WITH NO APU LEAKS OR ODORS NOTED. MAINTENANCE REPLACED BOTH HEPA FILTERS PER AMM 21-21-41.