# CVE-2020-8955: Memory corruption in n/a

> Remote attackers can cause a denial of service via buffer overflow in WeeChat by sending a malformed IRC channel mode message.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Feb 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-8955, GHSA-j94p-wg5x-c7xg, MGASA-2020-0122, UBUNTU-CVE-2020-8955, openSUSE-SU-2020:0248-1

## What is CVE-2020-8955?

CVE-2020-8955 is a critical memory corruption vulnerability in Debian Debian Linux, published on 12 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

irc_mode_channel_update in plugins/irc/irc-mode.c in WeeChat through 2.7 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a malformed IRC message 324 (channel mode).

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-8955?

It affects 5 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `weechat` | SUSE:Package Hub 15 | All versions | 2.1-bp151.4.3.1 |
| `weechat` | SUSE:Package Hub 15 SP1 | All versions | 2.1-bp151.4.3.1 |
| `weechat` | openSUSE:Leap 15.1 | All versions | 2.1-bp151.4.3.1 |

Products: Debian Debian Linux, Fedoraproject Fedora, Opensuse Backports Sle, Opensuse Leap, Weechat Weechat.

## How do I fix CVE-2020-8955?

Upgrade to a fixed version.

## Is CVE-2020-8955 being exploited?

There is no known exploitation of CVE-2020-8955 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8955 and fix it if it is affected.

What it is: CVE-2020-8955 is a critical memory corruption vulnerability in Debian Debian Linux, published on 12 Feb 2020. 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-2020-8955 in the wild and no public exploit code.

Affected product: Debian Debian 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-2020-8955/ (Markdown: https://insights.sbomify.com/CVE-2020-8955/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8955
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8955
- OSV: https://osv.dev/vulnerability/CVE-2020-8955

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8955/
Summaries are generated and may contain mistakes; the official description above is the record.