# CVE-2026-89882: media: rkvdec: hevc: guard INTER_REF_PIC_SET_PRED index underflow

> A local attacker can trigger an integer underflow in the RKVDEC driver, causing out-of-bounds memory reads and potential system instability.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-89882, GHSA-w6ch-hfjf-3q38, UBUNTU-CVE-2026-89882

## What is CVE-2026-89882?

CVE-2026-89882 is a high-severity vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

media: rkvdec: hevc: guard INTER_REF_PIC_SET_PRED index underflow

st_ref_pic_set_prediction() computes the reference RPS index as
st_rps_idx - (delta_idx_minus1 + 1) per HEVC spec equation 7-59.
Both operands are u8, so when delta_idx_minus1 + 1 exceeds the
current index the subtraction wraps and the subsequent array access
at calculated_rps_st_sets[ref_rps_idx] reads far out of bounds.

A userspace V4L2 client that can open the RKVDEC m2m decoder can
submit an EXT_SPS_ST_RPS control with INTER_REF_PIC_SET_PRED set
and delta_idx_minus1 crafted to trigger the underflow.

Reject the entry early when the reference index would underflow.

## Which versions are affected by CVE-2026-89882?


## How do I fix CVE-2026-89882?

Apply the vendor's patch.

## Is CVE-2026-89882 being exploited?

There is no known exploitation of CVE-2026-89882 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89882 and fix it if it is affected.

What it is: CVE-2026-89882 is a high-severity vulnerability in Linux, published on 16 Sep 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-2026-89882 in the wild and no public exploit code.

Affected product: Linux. 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-2026-89882/ (Markdown: https://insights.sbomify.com/CVE-2026-89882/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89882
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89882
- OSV: https://osv.dev/vulnerability/CVE-2026-89882

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89882/
Summaries are generated and may contain mistakes; the official description above is the record.