How severe is CVE-2017-5340?

CVE-2017-5340 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-5340 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 17% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-5340?

CVE-2017-5340 primarily affects Php. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-5340?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-5340 published?

CVE-2017-5340 was published on 2017-01-11 and last updated on 2026-06-17.

CVE-2017-5340

CVE-2017-5340 is a critical-severity vulnerability in Php with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 17% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 17% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Php
Published: 2017-01-11
Last modified: 2026-06-17

Description

Zend/zend_hash.c in PHP before 7.0.15 and 7.1.x before 7.1.1 mishandles certain cases that require large array allocations, which allows remote attackers to execute arbitrary code or cause a denial of service (integer overflow, uninitialized memory access, and use of arbitrary destructor function pointers) via crafted serialized data.

Frequently asked questions

What is CVE-2017-5340?: Zend/zend_hash.c in PHP before 7.0.15 and 7.1.x before 7.1.1 mishandles certain cases that require large array allocations, which allows remote attackers to execute arbitrary code or cause a denial of service (integer overflow, uninitialized memory access, and use of arbitrary destructor function pointers) via crafted serialized data.
How severe is CVE-2017-5340?: CVE-2017-5340 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-5340 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 17% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-5340?: CVE-2017-5340 primarily affects Php. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-5340?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-5340 published?: CVE-2017-5340 was published on 2017-01-11 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*

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