# CVE-2026-57080: Denial of service in Net::BitTorrent

> Remote attackers can exhaust memory in applications using the Net::BitTorrent Perl library by sending maliciously large message length prefixes.

- **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:** 30 Jun 2026
- **Updated:** 20 Jul 2026
- **Also known as:** GHSA-7jr6-2jf4-6qc4, GHSA-h9mr-rh28-v9r2

## What is CVE-2026-57080?

CVE-2026-57080 is a high-severity denial of service vulnerability in SANKO Net::BitTorrent, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Net::BitTorrent versions through 2.1.0 for Perl allow remote memory exhaustion via an uncapped peer-wire message-length prefix.

The peer-wire framing in _process_messages trusts the 4-byte length prefix sent by a connected peer with no upper bound, while receive_data appends every inbound byte to the input buffer. A peer announces a length prefix of up to about 4 GiB and then streams bytes; the decoder waits until the buffer holds the full message before processing it, so the buffer grows without limit.

Peer connections are unauthenticated, so any peer in the swarm exhausts the downloading process's memory. The largest legitimate message is a 16 KiB piece block, so any announced length far above that is anomalous.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-57080?


## How do I fix CVE-2026-57080?

No fix has been published for CVE-2026-57080 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-57080 being exploited?

There is no known exploitation of CVE-2026-57080 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57080 and fix it if it is affected.

What it is: CVE-2026-57080 is a high-severity denial of service vulnerability in SANKO Net::BitTorrent, published on 30 Jun 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-2026-57080 in the wild and no public exploit code.

Affected product: SANKO Net::BitTorrent. 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-2026-57080/ (Markdown: https://insights.sbomify.com/CVE-2026-57080/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57080
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57080
- OSV: https://osv.dev/vulnerability/CVE-2026-57080

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57080/
Summaries are generated and may contain mistakes; the official description above is the record.