# CVE-2020-17525: Remote unauthenticated denial-of-service in Subversion mod_authz_svn > Remote attackers can crash the Subversion server by requesting a non-existent repository URL when specific authz options are enabled. - **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:** Yes - **Published:** 17 Mar 2021 - **Updated:** 13 Feb 2025 - **Also known as:** ALPINE-CVE-2020-17525, ALSA-2021:0507, AZL-6899, BIT-subversion-2020-17525, CLSA-2022-1660064148, DEBIAN-CVE-2020-17525, DLA-2646-1, DSA-4851-1, GHSA-w6m8-jhpf-wj94, MGASA-2021-0091, RHSA-2021:0507, RHSA-2021:0508, RHSA-2021:0509, RLSA-2021:0507, SUSE-SU-2021:0424-1, SUSE-SU-2021:0425-1, UBUNTU-CVE-2020-17525, USN-5322-1, openSUSE-SU-2021:0280-1 ## What is CVE-2020-17525? CVE-2020-17525 is a high-severity vulnerability in Debian Debian Linux, published on 17 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Subversion's mod_authz_svn module will crash if the server is using in-repository authz rules with the AuthzSVNReposRelativeAccessFile option and a client sends a request for a non-existing repository URL. This can lead to disruption for users of the service. This issue was fixed in mod_dav_svn+mod_authz_svn servers 1.14.1 and mod_dav_svn+mod_authz_svn servers 1.10.7 Weakness: CWE-476 (NULL Pointer Dereference) ## Which versions are affected by CVE-2020-17525? 1 open source package ship an affected version, including subversion. It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `subversion` | Bitnami | From 1.9.0 | 1.10.7, 1.14.1 | | `libserf` | AlmaLinux:8 | All versions | 1.3.9-9.module_el8.3.0+2053+ac338b6d | | `libserf` | AlmaLinux:8 | All versions | 1.3.9-9.module_el8.4.0+2266+ac338b6d | | `libserf` | AlmaLinux:8 | All versions | 1.3.9-9.module_el8.6.0+2912+eb1cdf5a | | `mod_dav_svn` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `mod_dav_svn` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `mod_dav_svn` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion-devel` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-devel` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion-devel` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion-gnome` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-gnome` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion-gnome` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion-javahl` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-libs` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-libs` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion-libs` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion-perl` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-perl` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion-perl` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `subversion-tools` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.3.0+2053+ac338b6d | | `subversion-tools` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.4.0+2266+ac338b6d | | `subversion-tools` | AlmaLinux:8 | All versions | 1.10.2-4.module_el8.5.0+73+aa7e29ed | | `utf8proc` | AlmaLinux:8 | All versions | 2.1.1-5.module_el8.3.0+2053+ac338b6d | | `utf8proc` | AlmaLinux:8 | All versions | 2.1.1-5.module_el8.4.0+2266+ac338b6d | | `utf8proc` | AlmaLinux:8 | All versions | 2.1.1-5.module_el8.6.0+2912+eb1cdf5a | | `libserf` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.3.9-9.module+el8.3.0+6671+2675c974 | | `libserf-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.3.9-9.module+el8.3.0+6671+2675c974 | | `libserf-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.3.9-9.module+el8.3.0+6671+2675c974 | | `mod_dav_svn` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `mod_dav_svn-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion-devel-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | | `subversion-gnome` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.10.2-4.module+el8.3.0+9886+ac338b6d | Products: Apache Subversion, Debian Debian Linux. ## How do I fix CVE-2020-17525? Upgrade subversion to a fixed version for your release line: 1.10.7 or 1.14.1. ## Is CVE-2020-17525 being exploited? There is no known exploitation of CVE-2020-17525 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2017-9800](https://insights.sbomify.com/CVE-2017-9800/): A maliciously constructed svn+ssh:// URL would cause Subversion clients before 1.8.19, 1.9.x before 1.9.7, and 1.10.0.x through 1.10.0-alpha (critical 9.8) - [CVE-2013-4246](https://insights.sbomify.com/CVE-2013-4246/): Denial of service in n/a (high 8.8) - [CVE-2015-5259](https://insights.sbomify.com/CVE-2015-5259/): Integer overflow in n/a (high 8.6) - [CVE-2024-45720](https://insights.sbomify.com/CVE-2024-45720/): Apache Subversion: Command line argument injection on Windows platforms (high 8.2) - [CVE-2015-0202](https://insights.sbomify.com/CVE-2015-0202/): Denial of service in n/a (high 7.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-17525 and fix it if it is affected. What it is: CVE-2020-17525 is a high-severity vulnerability in Debian Debian Linux, published on 17 Mar 2021. 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-2020-17525 in the wild and no public exploit code. Affected packages and fixed versions: - subversion (Bitnami): affected from 1.9.0; fixed in 1.10.7, 1.14.1 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-2020-17525/ (Markdown: https://insights.sbomify.com/CVE-2020-17525/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-17525 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-17525 - OSV: https://osv.dev/vulnerability/CVE-2020-17525 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-17525/ Summaries are generated and may contain mistakes; the official description above is the record.