# CVE-2026-123540: OpenAM before 16.1.4 Incomplete Attribute Encoding in SAML 1.x Form POST


- **Severity:** Low 2.0 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 8 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-gp9c-wgqc-wwg3, GHSA-pw99-8h4m-p3gm

## What is CVE-2026-123540?

CVE-2026-123540 is a low-severity vulnerability in OpenIdentityPlatform OpenAM, published on 8 Nov 2026. 

### Official description

OpenAM before 16.1.4 contains an incomplete output encoding vulnerability that allows a SAML 1.x identity provider to alter attribute values by injecting unencoded content into the service provider auto-submitted form. Attackers controlling a trusted identity provider can craft assertion attribute names or values that reach the target application in modified form, undermining the integrity of received attributes.

Weakness: CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-123540?


## How do I fix CVE-2026-123540?

No fix has been published for CVE-2026-123540 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123540 being exploited?

There is no known exploitation of CVE-2026-123540 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123540 and fix it if it is affected.

What it is: CVE-2026-123540 is a low-severity vulnerability in OpenIdentityPlatform OpenAM, published on 8 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123540 in the wild and no public exploit code.

Affected product: OpenIdentityPlatform OpenAM. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123540/ (Markdown: https://insights.sbomify.com/CVE-2026-123540/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123540
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123540
- OSV: https://osv.dev/vulnerability/CVE-2026-123540

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123540/
Summaries are generated and may contain mistakes; the official description above is the record.