What is CVE-2015-8878?

CVE-2015-8878 is a medium-severity vulnerability in PHP, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.9/10. Published 2016-05-22.

How severe is CVE-2015-8878?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Buffer overflow in PHP

CVE-2015-8878

main/php_open_temporary_file.c in PHP before 5.5.28 and 5.6.x before 5.6.12 does not ensure thread safety, which allows remote attackers to cause a denial of service (race condition and heap memory corruption) by leveraging an application that performs many temporary-file accesses.

Vulnerability class: Buffer Overflow

Published 2016-05-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.012 (68.1th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Weakness classification (CWE)

References

bugs.php.net/bug.php (Issue Tracking, Vendor Advisory)
www.php.net/ChangeLog-5.php (Vendor Advisory)

Frequently asked questions

What is CVE-2015-8878?: CVE-2015-8878 is a medium-severity vulnerability in PHP, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.9/10. Published 2016-05-22.
How severe is CVE-2015-8878?: Medium severity. CVSS v3 base score is 5.9 out of 10.