CVE-2020-8986

CVE-2020-8986 is a critical-severity vulnerability in Zend Zendto with a CVSS 3.x base score of 9.8. 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-754.

Key facts

• Severity: Critical (CVSS 3.x base score 9.8)
• CVSS v2: 7.5
• EPSS exploit prediction: 2% (72nd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-754
• Affected product: Zend Zendto
• Published: 2020-03-24
• Last modified: 2026-06-17

Description

lib/NSSDropbox.php in ZendTo prior to 5.22-2 Beta failed to properly check for equality when validating the session cookie, allowing an attacker to gain administrative access with a large number of requests.

Frequently asked questions

What is CVE-2020-8986?

lib/NSSDropbox.php in ZendTo prior to 5.22-2 Beta failed to properly check for equality when validating the session cookie, allowing an attacker to gain administrative access with a large number of requests.

How severe is CVE-2020-8986?

CVE-2020-8986 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-2020-8986 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-8986?

CVE-2020-8986 primarily affects Zend Zendto. In total, 123 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-8986?

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-2020-8986 published?

CVE-2020-8986 was published on 2020-03-24 and last updated on 2026-06-17.

References

• https://zend.to/changelog.php

Affected products (123)

• cpe:2.3:a:zend:zendto:3.10:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.11:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.12:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.13:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.20:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.51:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.52:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.53:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.54:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.55:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.56-2:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.57:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.58:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.59:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.60:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.61:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.62:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.63:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.64:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.65:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.70-2:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.71:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.72:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.73:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.74:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.75:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.90:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.91:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.92:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.93:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:3.94:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.00:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.01:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.02:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.03-3:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.05-2:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.06-2:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.07-1:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.08-4:*:*:*:*:*:*:*
• cpe:2.3:a:zend:zendto:4.09-1:*:*:*:*:*:*:*

More vulnerabilities in Zend Zendto

• CVE-2020-8985 — High (CVSS 8.8): ZendTo prior to 5.22-2 Beta allowed reflected XSS and CSRF via the unlock.tpl unlock user functionality.
• CVE-2020-8984 — High (CVSS 7.5): lib/NSSDropbox.php in ZendTo prior to 5.22-2 Beta allowed IP address spoofing via the X-Forwarded-For header.
• CVE-2021-27888 — Medium (CVSS 6.1): ZendTo before 6.06-4 Beta allows XSS during the display of a drop-off in which a filename has unexpected characters.
• CVE-2018-1000841 — Medium (CVSS 6.1): Zend.To version Prior to 5.15-1 contains a Cross Site Scripting (XSS) vulnerability in The verify.php page that can…
• CVE-2013-6808 — Medium (CVSS 4.3): Cross-site scripting (XSS) vulnerability in lib/NSSDropoff.php in ZendTo before 4.11-13 allows remote attackers to…

All CVEs affecting Zend Zendto →

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• CVE-2024-7826 — Critical (CVSS 9.8): Improper Check for Unusual or Exceptional Conditions vulnerability in Webroot SecureAnywhere - Web Shield on Windows,…
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