How severe is CVE-2016-6496?

CVE-2016-6496 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-2016-6496 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6496?

CVE-2016-6496 primarily affects Atlassian Crowd. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6496?

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-2016-6496 published?

CVE-2016-6496 was published on 2016-12-09 and last updated on 2026-06-17.

CVE-2016-6496

CVE-2016-6496 is a critical-severity vulnerability in Atlassian Crowd 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Atlassian Crowd
Published: 2016-12-09
Last modified: 2026-06-17

Description

The LDAP directory connector in Atlassian Crowd before 2.8.8 and 2.9.x before 2.9.5 allows remote attackers to execute arbitrary code via an LDAP attribute with a crafted serialized Java object, aka LDAP entry poisoning.

Frequently asked questions

What is CVE-2016-6496?: The LDAP directory connector in Atlassian Crowd before 2.8.8 and 2.9.x before 2.9.5 allows remote attackers to execute arbitrary code via an LDAP attribute with a crafted serialized Java object, aka LDAP entry poisoning.
How severe is CVE-2016-6496?: CVE-2016-6496 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-2016-6496 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6496?: CVE-2016-6496 primarily affects Atlassian Crowd. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6496?: 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-2016-6496 published?: CVE-2016-6496 was published on 2016-12-09 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:atlassian:crowd:*:*:*:*:*:*:*:*
cpe:2.3:a:atlassian:crowd:2.9.0:*:*:*:*:*:*:*
cpe:2.3:a:atlassian:crowd:2.9.1:*:*:*:*:*:*:*

More vulnerabilities in Atlassian Crowd

CVE-2022-43782 — Critical (CVSS 9.8): Affected versions of Atlassian Crowd allow an attacker to authenticate as the crowd application via security…
CVE-2022-26136 — Critical (CVSS 9.8): A vulnerability in multiple Atlassian products allows a remote, unauthenticated attacker to bypass Servlet Filters used…
CVE-2019-11580 — Critical (CVSS 9.8): Atlassian Crowd and Crowd Data Center had the pdkinstall development plugin incorrectly enabled in release builds.…
CVE-2012-2926 — Critical (CVSS 9.1): Atlassian JIRA before 5.0.1; Confluence before 3.5.16, 4.0 before 4.0.7, and 4.1 before 4.1.10; FishEye and Crucible…
CVE-2023-22521 — High (CVSS 8.8): This High severity RCE (Remote Code Execution) vulnerability was introduced in version 3.4.6 of Crowd Data Center and…
CVE-2022-26137 — High (CVSS 8.8): A vulnerability in multiple Atlassian products allows a remote, unauthenticated attacker to cause additional Servlet…

All CVEs affecting Atlassian Crowd →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →