CVE-2015-6835
The session deserializer in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 mishandles multiple php_var_unserialize calls, which allow remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via crafted…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 36.2%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
The session deserializer in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 mishandles multiple php_var_unserialize calls, which allow remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via crafted session content.
- CVSS 3.0
- 9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 36.16% probability · 98th percentile
- Public exploits
- 1 in Exploit-DB · verified · first 9 September 2015
- CISA KEV
- Not listed
- Affected
- php/php
- Source
- security@opentext.com
EPSS moved from 31.9% on 21 September 2026 to 36.2% on 4 November 2026, peaking at 37.0% on 22 September 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- http://php.net/ChangeLog-5.php
- http://www.debian.org/security/2015/dsa-3358
- http://www.securityfocus.com/bid/76734
- http://www.securitytracker.com/id/1033548
- https://bugs.php.net/bug.php?id=70219
- https://security.gentoo.org/glsa/201606-10
- http://php.net/ChangeLog-5.php
- http://www.debian.org/security/2015/dsa-3358
- http://www.securityfocus.com/bid/76734
- http://www.securitytracker.com/id/1033548
- https://bugs.php.net/bug.php?id=70219
- https://security.gentoo.org/glsa/201606-10
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.