How severe is CVE-2019-12331?

CVE-2019-12331 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-12331 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-12331?

CVE-2019-12331 affects Phpoffice Phpspreadsheet. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-12331?

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

When was CVE-2019-12331 published?

CVE-2019-12331 was published on 2019-11-07 and last updated on 2026-06-17.

CVE-2019-12331

CVE-2019-12331 is a high-severity vulnerability in Phpoffice Phpspreadsheet with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-611.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-611
Affected product: Phpoffice Phpspreadsheet
Published: 2019-11-07
Last modified: 2026-06-17

Description

PHPOffice PhpSpreadsheet before 1.8.0 has an XXE issue. The XmlScanner decodes the sheet1.xml from an .xlsx to utf-8 if something else than UTF-8 is declared in the header. This was a security measurement to prevent CVE-2018-19277 but the fix is not sufficient. By double-encoding the the xml payload to utf-7 it is possible to bypass the check for the string ‚<!ENTITY‘ and thus allowing for an xml external entity processing (XXE) attack.

Frequently asked questions

What is CVE-2019-12331?: PHPOffice PhpSpreadsheet before 1.8.0 has an XXE issue. The XmlScanner decodes the sheet1.xml from an .xlsx to utf-8 if something else than UTF-8 is declared in the header. This was a security measurement to prevent CVE-2018-19277 but the fix is not sufficient. By double-encoding the the xml payload to utf-7 it is possible to bypass the check for the string ‚<!ENTITY‘ and thus allowing for an xml external entity processing (XXE) attack.
How severe is CVE-2019-12331?: CVE-2019-12331 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-12331 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-12331?: CVE-2019-12331 affects Phpoffice Phpspreadsheet. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-12331?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-12331 published?: CVE-2019-12331 was published on 2019-11-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:phpoffice:phpspreadsheet:*:*:*:*:*:*:*:*

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