What is CVE-2008-2108?

CVE-2008-2108 is a critical-severity vulnerability in PHP, classified under Insufficient Entropy. CVSS score: 9.8/10. Published 2008-05-07.

How severe is CVE-2008-2108?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in PHP

CVE-2008-2108

The GENERATE_SEED macro in PHP 4.x before 4.4.8 and 5.x before 5.2.5, when running on 64-bit systems, performs a multiplication that generates a portion of zero bits during conversion due to insufficient precision, which produces 24 bits of entropy and simplifies brute force attacks against protection mechanisms that use the rand and mt_rand functions.

Published 2008-05-07 · last modified 2026-06-16.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.043 (90.8th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 90.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.043 · newest: 0.043 · change: 0.000

Affected products

PHP
Canonical Ubuntu Linux — versions 6.06, 7.04, 7.10
Debian Linux — versions 4.0
Fedoraproject Fedora — versions 8, 9

Weakness classification (CWE)

CWE-331 — Insufficient Entropy

References

www.redhat.com/archives/fedora-package-announce/2008-June/msg00779.html (vendor-advisory, Mailing List)
secunia.com/advisories/32746 (Broken Link, third-party-advisory)
archives.neohapsis.com/archives/fulldisclosure/2008-05/0103.html (mailing-list, Exploit, Broken Link)
security.gentoo.org/glsa/glsa-200811-05.xml (vendor-advisory, Third Party Advisory)
www.redhat.com/support/errata/RHSA-2008-0546.html (vendor-advisory, Broken Link)
www.redhat.com/archives/fedora-package-announce/2008-June/msg00773.html (vendor-advisory, Mailing List)
secunia.com/advisories/30828 (Broken Link, third-party-advisory)
www.mandriva.com/security/advisories (vendor-advisory, Broken Link)
securityreason.com/securityalert/3859 (Mailing List, third-party-advisory)
www.redhat.com/support/errata/RHSA-2008-0582.html (vendor-advisory, Broken Link)

Frequently asked questions

What is CVE-2008-2108?: CVE-2008-2108 is a critical-severity vulnerability in PHP, classified under Insufficient Entropy. CVSS score: 9.8/10. Published 2008-05-07.
How severe is CVE-2008-2108?: Critical severity. CVSS v3 base score is 9.8 out of 10.