CVE-2015-1555

Zend/Session/SessionManager in Zend Framework 2.2.x before 2.2.9, 2.3.x before 2.3.4 allows remote attackers to create valid sessions without using session validators.

Published: 2017-08-07 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-1555 is rated Moderate Risk (61.6/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.39%). EPSS rose +1.10% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-1555

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.29% 1.39% +1.10%
2 2025-03-30 0.56% 0.29% -0.27%
3 2025-03-29 — 0.56% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-1555

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2015-1555

OS Trackers for CVE-2015-1555

vendor priority summary link
ubuntu medium CVE-2015-1555 medium priority: Ubuntu including 2 source packages (zend-framework, zendframework), 13 status rows across 7 suites (artful, bionic, trusty, upstream, wily, xenial, zesty): DNE 7, ignored 2, not-affected 2, released 2. https://ubuntu.com/security/CVE-2015-1555

Affected software / configurations for CVE-2015-1555

Vendor Product Version Raw CPE
zend zend_framework 2.2.0 cpe:2.3:a:zend:zend_framework:2.2.0:*:*:*:*:*:*:*
zend zend_framework 2.2.1 cpe:2.3:a:zend:zend_framework:2.2.1:*:*:*:*:*:*:*
zend zend_framework 2.2.2 cpe:2.3:a:zend:zend_framework:2.2.2:*:*:*:*:*:*:*
zend zend_framework 2.2.3 cpe:2.3:a:zend:zend_framework:2.2.3:*:*:*:*:*:*:*
zend zend_framework 2.2.4 cpe:2.3:a:zend:zend_framework:2.2.4:*:*:*:*:*:*:*
zend zend_framework 2.2.5 cpe:2.3:a:zend:zend_framework:2.2.5:*:*:*:*:*:*:*
zend zend_framework 2.2.6 cpe:2.3:a:zend:zend_framework:2.2.6:*:*:*:*:*:*:*
zend zend_framework 2.2.7 cpe:2.3:a:zend:zend_framework:2.2.7:*:*:*:*:*:*:*
zend zend_framework 2.2.8 cpe:2.3:a:zend:zend_framework:2.2.8:*:*:*:*:*:*:*
zend zend_framework 2.3.0 cpe:2.3:a:zend:zend_framework:2.3.0:*:*:*:*:*:*:*
zend zend_framework 2.3.1 cpe:2.3:a:zend:zend_framework:2.3.1:*:*:*:*:*:*:*
zend zend_framework 2.3.2 cpe:2.3:a:zend:zend_framework:2.3.2:*:*:*:*:*:*:*
zend zend_framework 2.3.3 cpe:2.3:a:zend:zend_framework:2.3.3:*:*:*:*:*:*:*

References for CVE-2015-1555

cvelogic Threat Intelligence