# CVE-2026-123543: OpenAM before 16.1.4 Unauthenticated DoS via Unbounded Java Deserialisation

Status: published. Published: 2026-11-08. Updated: 2026-11-12.

OpenAM before 16.1.4 contains a denial of service vulnerability that allows unauthenticated attackers to exhaust server resources by sending serialized Java data without size or structure limits. Attackers can send small crafted requests to remote SDK endpoints, classic login pages, or the administration console to block authentication, session validation and policy decisions.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- OpenIdentityPlatform / OpenAM (org.openidentityplatform.openam/openam-shared): ≥ 0; < 16.1.4 (affected, semver); 16.1.4 (unaffected, semver). Source: CNA: VulnCheck
- OpenIdentityPlatform / OpenAM (org.openidentityplatform.openam/openam-core): ≥ 0; < 16.1.4 (affected, semver); 16.1.4 (unaffected, semver). Source: CNA: VulnCheck
- OpenIdentityPlatform / OpenAM (org.openidentityplatform.openam/openam-clientsdk): ≥ 0; < 16.1.4 (affected, semver); 16.1.4 (unaffected, semver). Source: CNA: VulnCheck
- OpenIdentityPlatform / OpenAM (org.openidentityplatform.openam/openam-server-only): ≥ 0; < 16.1.4 (affected, semver); 16.1.4 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.7 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 8.7 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.39% as of 2026-11-12; percentile 34.13%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-x7wr-5gxg-v833 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/openam-before-16.1.4-unauthenticated-dos-via-unbounded-java-deserialisation (CNA: VulnCheck; third-party-advisory)

- https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-x7wr-5gxg-v833 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/openam-before-16.1.4-unauthenticated-dos-via-unbounded-java-deserialisation (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123543; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123543; retrieved 2026-11-11; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123543; retrieved 2026-11-12; source updated Not reported

Revision: 43e2b4c6f0866cbc344d70eab687288d6c9a0a1fed1d15c1cebf4b4c95cccd27

Canonical: https://y2.dev/cve/CVE-2026-123543

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