# CVE-2026-40953: Heap overflow in Secure Access clients

> Local administrators can cause a denial of service in Secure Access clients via a heap overflow in certificate parsing.

- **Severity:** Medium 6.7 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jul 2026
- **Updated:** 16 Jul 2026
- **Also known as:** GHSA-9vvg-8c87-463f

## What is CVE-2026-40953?

CVE-2026-40953 is a medium-severity memory corruption vulnerability in Absolute Secure Access, published on 15 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

CVE-2026-40953 is a heap overflow in the
certificate parsing function of Secure Access clients prior to 14.55. Attackers
with local access and administrator permissions can create a denial of service
attack against the client over which they have control.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-40953?

It affects 1 product.


Products: Absolute Secure Access.

## How do I fix CVE-2026-40953?

No fix has been published for CVE-2026-40953 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40953 being exploited?

There is no known exploitation of CVE-2026-40953 in the wild and no public exploit code.

## Other vulnerabilities in Absolute Secure Access

- [CVE-2026-55402](https://insights.sbomify.com/CVE-2026-55402/): Denial of service in Secure Access (high 8.7)
- [CVE-2026-33445](https://insights.sbomify.com/CVE-2026-33445/): Memory management vulnerability in Secure Access servers (high 8.7)
- [CVE-2025-49080](https://insights.sbomify.com/CVE-2025-49080/): Memory management vulnerability in Absolute Secure Access server versions 9.0 to 13.54 (high 8.7)
- [CVE-2026-40952](https://insights.sbomify.com/CVE-2026-40952/): Privilge misconfiguration in Secure Access installers (high 8.5)
- [CVE-2026-33451](https://insights.sbomify.com/CVE-2026-33451/): Arbitrary read/write vulnerability in Windows clients prior to 14.50 (high 8.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40953 and fix it if it is affected.

What it is: CVE-2026-40953 is a medium-severity memory corruption vulnerability in Absolute Secure Access, published on 15 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40953 in the wild and no public exploit code.

Affected product: Absolute Secure Access. 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-2026-40953/ (Markdown: https://insights.sbomify.com/CVE-2026-40953/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40953
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40953
- OSV: https://osv.dev/vulnerability/CVE-2026-40953

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40953/
Summaries are generated and may contain mistakes; the official description above is the record.