# CVE-2026-8451: Insufficient input validation leading to memory overread

> Attackers can read sensitive memory contents from NetScaler devices configured as SAML IDPs due to insufficient input validation.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Jun 2026
- **Updated:** 30 Jun 2026
- **Also known as:** GHSA-6659-v5cc-894x

## What is CVE-2026-8451?

CVE-2026-8451 is a high-severity vulnerability in NetScaler ADC, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler ADC or NetScaler Gateway is configured as a SAML IDP

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-8451?

It affects 2 products.


Products: Citrix NetScaler ADC, Citrix Netscaler Gateway.

## How do I fix CVE-2026-8451?

No fix has been published for CVE-2026-8451 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-8451 being exploited?

There is no known exploitation of CVE-2026-8451 in the wild and no public exploit code.

Public exploit code:

- https://github.com/watchtowrlabs/watchTowr-vs-Netscaler-CVE-2026-8451 (github_poc): https://github.com/watchtowrlabs/watchTowr-vs-Netscaler-CVE-2026-8451
- Citrix NetScaler CVE Preconditions Checker as per CTX696604 | Supported CVE : CVE-2026-8451, CVE-2026-8452, CVE-2026-8655, CVE-2026-10816, CVE-2026-10817, and CVE-2026-13474 (github_poc): https://github.com/derekpreston81/CVE_ADC_IOC_2026
- CVE-2026-8451 (github_poc): https://github.com/0xredash/CVE-2026-8451
- https://github.com/attarwahyup/Netscaler-CVE-2026-8451 (github_poc): https://github.com/attarwahyup/Netscaler-CVE-2026-8451

## Other vulnerabilities in NetScaler ADC

- [CVE-2023-3519](https://insights.sbomify.com/CVE-2023-3519/): Citrix NetScaler ADC and NetScaler Gateway Code Injection (critical 9.8, exploited in the wild)
- [CVE-2026-88771](https://insights.sbomify.com/CVE-2026-88771/): Citrix NetScaler Improper Input Validation (critical 9.5, exploited in the wild)
- [CVE-2026-88772](https://insights.sbomify.com/CVE-2026-88772/): Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer (critical 9.5, exploited in the wild)
- [CVE-2023-4966](https://insights.sbomify.com/CVE-2023-4966/): Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow (critical 9.4, exploited in the wild)
- [CVE-2026-19490](https://insights.sbomify.com/CVE-2026-19490/): Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel (critical 9.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8451 and fix it if it is affected.

What it is: CVE-2026-8451 is a high-severity vulnerability in NetScaler ADC, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-8451 in the wild and no public exploit code.

Affected product: NetScaler ADC. 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-2026-8451/ (Markdown: https://insights.sbomify.com/CVE-2026-8451/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8451
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8451
- OSV: https://osv.dev/vulnerability/CVE-2026-8451

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8451/
Summaries are generated and may contain mistakes; the official description above is the record.