CVE-2026-87806

HIGH
Published Sep 9, 2026 Modified Sep 10, 2026 CWE-287

Description

Parse Server versions <= 8.6.87 and >= 9.0.0 < 9.10.1-alpha.7 contain an authentication bypass in the built-in LDAP authentication adapter. The adapter forwarded the client-supplied password to the directory without verifying that a password had been supplied, and treated any non-error response from the directory as proof of authentication. A zero-length credential turns an LDAP simple bind into the unauthenticated authentication mechanism described in RFC 4513 section 5.1.2, which some directories (including Active Directory in its default configuration) answer with success while mapping the connection to anonymous. As a result, an unauthenticated attacker who knows a directory username can obtain a valid session token for that account, resulting in account takeover. Only deployments that enable the LDAP authentication adapter are affected, and deployments whose directory refuses unauthenticated simple bind (such as a stock OpenLDAP configuration) are not exploitable. The issue is fixed in 8.6.88 and 9.10.1-alpha.7, which require the password to be a non-empty string and reject the request before contacting the directory.

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CVSS v3.1 Score

7.4
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0029
Probability of exploitation
0.22%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

References

Frequently Asked Questions

What is CVE-2026-87806? +
Parse Server versions <= 8.6.87 and >= 9.0.0 < 9.10.1-alpha.7 contain an authentication bypass in the built-in LDAP authentication adapter. The adapter forwarded the client-supplied password to the directory without verifying that a password had been supplied, and treated any non-error response from the directory as proof of authentication. A zero-length credential turns an LDAP simple bind into the unauthenticated authentication mechanism described in RFC 4513 section 5.1.2, which some directories (including Active Directory in its default configuration) answer with success while mapping the connection to anonymous. As a result, an unauthenticated attacker who knows a directory username can obtain a valid session token for that account, resulting in account takeover. Only deployments that enable the LDAP authentication adapter are affected, and deployments whose directory refuses unauthenticated simple bind (such as a stock OpenLDAP configuration) are not exploitable. The issue is fixed in 8.6.88 and 9.10.1-alpha.7, which require the password to be a non-empty string and reject the request before contacting the directory. It has a CVSS v3.1 base score of 7.4 (HIGH).
How severe is CVE-2026-87806? +
CVE-2026-87806 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-87806? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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