# CVE-2020-25600: Memory corruption in n/a > An unprivileged guest can cause memory corruption in the hypervisor, leading to a system-wide Denial of Service. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 23 Sep 2020 - **Updated:** 4 Aug 2024 - **Also known as:** ALPINE-CVE-2020-25600, DEBIAN-CVE-2020-25600, GHSA-gff7-q4h3-6x9j, UBUNTU-CVE-2020-25600 ## What is CVE-2020-25600? CVE-2020-25600 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 23 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description An issue was discovered in Xen through 4.14.x. Out of bounds event channels are available to 32-bit x86 domains. The so called 2-level event channel model imposes different limits on the number of usable event channels for 32-bit x86 domains vs 64-bit or Arm (either bitness) ones. 32-bit x86 domains can use only 1023 channels, due to limited space in their shared (between guest and Xen) information structure, whereas all other domains can use up to 4095 in this model. The recording of the respective limit during domain initialization, however, has occurred at a time where domains are still deemed to be 64-bit ones, prior to actually honoring respective domain properties. At the point domains get recognized as 32-bit ones, the limit didn't get updated accordingly. Due to this misbehavior in Xen, 32-bit domains (including Domain 0) servicing other domains may observe event channel allocations to succeed when they should really fail. Subsequent use of such event channels would then possibly lead to corruption of other parts of the shared info structure. An unprivileged guest may cause another domain, in particular Domain 0, to misbehave. This may lead to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only x86 32-bit domains servicing other domains are vulnerable. Arm systems, as well as x86 64-bit domains, are not vulnerable. Weakness: CWE-787 (Out-of-bounds Write) ## Which versions are affected by CVE-2020-25600? It affects 4 products. Products: Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap, Xen Xen. ## How do I fix CVE-2020-25600? Apply the vendor's patch. ## Is CVE-2020-25600 being exploited? There is no known exploitation of CVE-2020-25600 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-2020-25600 and fix it if it is affected. What it is: CVE-2020-25600 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 23 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2020-25600 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-2020-25600/ (Markdown: https://insights.sbomify.com/CVE-2020-25600/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25600 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25600 - OSV: https://osv.dev/vulnerability/CVE-2020-25600 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-25600/ Summaries are generated and may contain mistakes; the official description above is the record.