Josh Kupershmidt discovered the pgCrypto extension could expose several bytes of server memory if the crypt() function was provided a too-short salt. An attacker could use this flaw to read private data. (CVE-2015-5288)
Oskari Saarenmaa discovered that the json and jsonb handlers could exhaust available stack space. An attacker could use this flaw to perform a denial of service attack. (CVE-2015-5289)
The postgresql9.3 and postgresql9.4 packages have been updated to versions 9.3.10 and 9.4.5, respectively, to fix these issues. See the upstream release notes for more details.