# CVE-2026-48682: Memory corruption in n/a

> An out-of-bounds read in FastNetMon's IPv4 parser allows attackers to cause denial of service or disclose memory via crafted packets.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Jun 2026
- **Updated:** 4 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-48682, GHSA-p5cp-vqjq-6cj7, UBUNTU-CVE-2026-48682

## What is CVE-2026-48682?

CVE-2026-48682 is a medium-severity memory corruption vulnerability in n/a, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the IPv4 packet parser. In src/simple_packet_parser_ng.cpp, after validating that the packet contains at least sizeof(ipv4_header_t) bytes (20 bytes), the code advances the local_pointer by '4 * ipv4_header->get_ihl()' (line 164) without validating that (a) IHL >= 5 (the minimum valid value per RFC 791), or (b) 4 * IHL bytes are actually available in the packet. The IHL field is 4 bits, allowing values 0-15, so the advance can be 0-60 bytes. An IHL value of 15 with only 20 bytes validated causes a 40-byte over-read. An IHL of 0-4 causes the pointer to not advance past the IP header, resulting in the TCP/UDP header being parsed from IP header data (type confusion). This vulnerability is reachable via any packet capture interface.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-48682?


## How do I fix CVE-2026-48682?

No fix has been published for CVE-2026-48682 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-48682 being exploited?

There is no known exploitation of CVE-2026-48682 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48682 and fix it if it is affected.

What it is: CVE-2026-48682 is a medium-severity memory corruption vulnerability in n/a, published on 2 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-2026-48682 in the wild and no public exploit code.

Affected product: n/a. 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-2026-48682/ (Markdown: https://insights.sbomify.com/CVE-2026-48682/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48682
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48682
- OSV: https://osv.dev/vulnerability/CVE-2026-48682

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48682/
Summaries are generated and may contain mistakes; the official description above is the record.