# CVE-2026-55687: ESF-IDF: Stack-Based Out-of-Bounds Write in JPEG Decoder DQT Marker Parsing

> Attackers can cause denial of service via stack memory corruption in the JPEG decoder by sending malformed DQT markers in ESP-IDF.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jul 2026
- **Updated:** 10 Jul 2026
- **Also known as:** GHSA-v6r2-f6p2-88cj

## What is CVE-2026-55687?

CVE-2026-55687 is a high-severity memory corruption vulnerability in espressif esp-idf, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. Versions 6.0.1, 5.5.4, 5.4.4, 5.3.5, and possibly prior contain an out-of-bounds write in jpeg_parse_dqt_marker() in components/esp_driver_jpeg/jpeg_parse_marker.c because the attacker-controlled DQT marker Tq nibble is used as an index into the qt_tbl array without validating that it is in the range 0..3, allowing malformed JPEG input to corrupt stack memory and reliably trigger a denial of service. This issue is fixed in version 6.0.2 and is expected to be fixed in versions 5.5.5, 5.4.5, and 5.3.6.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-55687?


## How do I fix CVE-2026-55687?

No fix has been published for CVE-2026-55687 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55687 being exploited?

There is no known exploitation of CVE-2026-55687 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55687 and fix it if it is affected.

What it is: CVE-2026-55687 is a high-severity memory corruption vulnerability in espressif esp-idf, published on 10 Jul 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-2026-55687 in the wild and no public exploit code.

Affected product: espressif esp-idf. 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-2026-55687/ (Markdown: https://insights.sbomify.com/CVE-2026-55687/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55687
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55687
- OSV: https://osv.dev/vulnerability/CVE-2026-55687

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55687/
Summaries are generated and may contain mistakes; the official description above is the record.