Here are the details from the Slackware 13.37 ChangeLog:
+--------------------------+
patches/packages/php-5.3.15-i486-1_slack13.37.txz: Upgraded.
Fixed potential overflow in _php_stream_scandir (CVE-2012-2688).
(Thanks to Jason Powell, Stas)
For more information, see:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-2688
(* Security fix *)
+--------------------------+


Where to find the new packages:
+-----------------------------+

Thanks to the friendly folks at the OSU Open Source Lab
(http://osuosl.org) for donating FTP and rsync hosting
to the Slackware project! :-)

Also see the "Get Slack" section on http://slackware.com for
additional mirror sites near you.

Updated package for Slackware 12.0:
ftp://ftp.slackware.com/pub/slackware/slackware-12.0/patches/packages/php-5.3.15-i486-1_slack12.0.tgz

Updated package for Slackware 12.1:
ftp://ftp.slackware.com/pub/slackware/slackware-12.1/patches/packages/php-5.3.15-i486-1_slack12.1.tgz

Updated package for Slackware 12.2:
ftp://ftp.slackware.com/pub/slackware/slackware-12.2/patches/packages/php-5.3.15-i486-1_slack12.2.tgz

Updated package for Slackware 13.0:
ftp://ftp.slackware.com/pub/slackware/slackware-13.0/patches/packages/php-5.3.15-i486-1_slack13.0.txz

Updated package for Slackware x86_64 13.0:
ftp://ftp.slackware.com/pub/slackware/slackware64-13.0/patches/packages/php-5.3.15-x86_64-1_slack13.0.txz

Updated package for Slackware 13.1:
ftp://ftp.slackware.com/pub/slackware/slackware-13.1/patches/packages/php-5.3.15-i486-1_slack13.1.txz

Updated package for Slackware x86_64 13.1:
ftp://ftp.slackware.com/pub/slackware/slackware64-13.1/patches/packages/php-5.3.15-x86_64-1_slack13.1.txz

Updated package for Slackware 13.37:
ftp://ftp.slackware.com/pub/slackware/slackware-13.37/patches/packages/php-5.3.15-i486-1_slack13.37.txz

Updated package for Slackware x86_64 13.37:
ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/patches/packages/php-5.3.15-x86_64-1_slack13.37.txz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/n/php-5.4.5-i486-1.txz

Updated package for Slackware x86_64 -current:
ftp://ftp.slackware.com/pub/slackware/slackware64-current/slackware64/n/php-5.4.5-x86_64-1.txz


MD5 signatures:
+-------------+

Slackware 12.0 package:
301d8b0a7022a652b56c12f2e7907c0c php-5.3.15-i486-1_slack12.0.tgz

Slackware 12.1 package:
1e3e081bef9e945f179395da2e67392c php-5.3.15-i486-1_slack12.1.tgz

Slackware 12.2 package:
8131db9a666e327f7afc0356208c57ea php-5.3.15-i486-1_slack12.2.tgz

Slackware 13.0 package:
1f84307bd0492300bdbc3bda1cda0cfa php-5.3.15-i486-1_slack13.0.txz

Slackware x86_64 13.0 package:
1b0dddcd12bcdcd8ffaefac6a50bb5e6 php-5.3.15-x86_64-1_slack13.0.txz

Slackware 13.1 package:
7f04ac2bd39f45fbcb9dc8013df5f6a8 php-5.3.15-i486-1_slack13.1.txz

Slackware x86_64 13.1 package:
46959f30b4532a0ca0fc22e91dcb9f6b php-5.3.15-x86_64-1_slack13.1.txz

Slackware 13.37 package:
80d9351af3bbd9a1cf2a8574e2df4304 php-5.3.15-i486-1_slack13.37.txz

Slackware x86_64 13.37 package:
30c6a34e55f77143f768fe6ae43caa06 php-5.3.15-x86_64-1_slack13.37.txz

Slackware -current package:
e4dd41a890cde64e19e41d31c8447fa8 n/php-5.4.5-i486-1.txz

Slackware x86_64 -current package:
8329be52ae2863aba8b2155c568b25df n/php-5.4.5-x86_64-1.txz


Installation instructions:
+------------------------+

Upgrade the package as root:
# upgradepkg php-5.3.15-i486-1_slack13.37.txz

Then, restart Apache httpd:
# /etc/rc.d/rc.httpd stop
# /etc/rc.d/rc.httpd start


+-----+

Slackware Linux Security Team
http://slackware.com/gpg-key