# CVE-2026-82520: parsedmarc < 11.0.1 Zip Bomb DoS via Compressed Email Attachments

> An unauthenticated remote attacker can cause a denial of service by sending crafted emails with highly compressed attachments to the monitored mailbox.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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:** 3 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** GHSA-43qf-f35w-2x4r

## What is CVE-2026-82520?

CVE-2026-82520 is a high-severity denial of service vulnerability in domainaware parsedmarc, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

parsedmarc before 11.0.1 decompresses gzip and ZIP attachments in a single unbounded read with no limit on decompressed output size. Because parsedmarc automatically processes incoming DMARC report emails without user interaction, an unauthenticated remote attacker can send a crafted email with a highly compressed attachment to the monitored mailbox, causing the parsedmarc process to allocate memory proportional to the uncompressed size and exhaust available RAM.

Weakness: CWE-409 (Improper Handling of Highly Compressed Data (Data Amplification))

## Which versions are affected by CVE-2026-82520?


## How do I fix CVE-2026-82520?

No fix has been published for CVE-2026-82520 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-82520 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82520 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82520 and fix it if it is affected.

What it is: CVE-2026-82520 is a high-severity denial of service vulnerability in domainaware parsedmarc, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82520 exists.

Affected product: domainaware parsedmarc. 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-2026-82520/ (Markdown: https://insights.sbomify.com/CVE-2026-82520/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82520
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82520
- OSV: https://osv.dev/vulnerability/CVE-2026-82520

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82520/
Summaries are generated and may contain mistakes; the official description above is the record.