# CVE-2026-53763: OP-TEE has AES-GCM 32-bit integer overflow in length counters that breaks authentication guarantee

> Integer overflow in OP-TEE AES-GCM implementation breaks authentication tags for large payloads, allowing security bypass in Trusted Execution Environments.

- **Severity:** Low 3.8 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Jul 2026
- **Updated:** 7 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-53763, GHSA-fcm8-vjhf-6vqh, UBUNTU-CVE-2026-53763

## What is CVE-2026-53763?

CVE-2026-53763 is a low-severity vulnerability in OP-TEE optee_os, published on 6 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.0.0 and prior to version 4.11.0, 32-bit integer overflows in OP-TEE core's AES-GCM implementation cause the authentication tag to be computed with incorrect bit-length values after processing more than 512 megabytes of payload or Additional Authenticated Data (AAD). Version 4.11.0 contains a patch. No known workarounds are available.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-53763?

It affects 1 product.


Products: Trustedfirmware Op-Tee.

## How do I fix CVE-2026-53763?

No fix has been published for CVE-2026-53763 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53763 being exploited?

There is no known exploitation of CVE-2026-53763 in the wild and no public exploit code.

## Other vulnerabilities in OP-TEE optee_os

- [CVE-2019-1010292](https://insights.sbomify.com/CVE-2019-1010292/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010293](https://insights.sbomify.com/CVE-2019-1010293/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010295](https://insights.sbomify.com/CVE-2019-1010295/): Linaro/OP-TEE OP-TEE 3.3.0 and earlier is affected by: Buffer Overflow. (critical 9.8)
- [CVE-2019-1010296](https://insights.sbomify.com/CVE-2019-1010296/): Memory corruption in OP-TEE (critical 9.8)
- [CVE-2019-1010297](https://insights.sbomify.com/CVE-2019-1010297/): Memory corruption in OP-TEE (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53763 and fix it if it is affected.

What it is: CVE-2026-53763 is a low-severity vulnerability in OP-TEE optee_os, published on 6 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-2026-53763 in the wild and no public exploit code.

Affected product: OP-TEE optee_os. 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-2026-53763/ (Markdown: https://insights.sbomify.com/CVE-2026-53763/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53763
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53763
- OSV: https://osv.dev/vulnerability/CVE-2026-53763

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-53763/
Summaries are generated and may contain mistakes; the official description above is the record.