{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2023-39953 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2023-39953 yet. Limit exposure of the affected software until one is available.","what":"CVE-2023-39953 is a medium-severity authentication bypass vulnerability in nextcloud security-advisories, published on 10 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2023-39953 and fix it if it is affected.\n\nWhat it is: CVE-2023-39953 is a medium-severity authentication bypass vulnerability in nextcloud security-advisories, published on 10 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2023-39953 in the wild and no public exploit code.\n\nAffected product: nextcloud security-advisories. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. 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.\n2. 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.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2023-39953/ (Markdown: https://insights.sbomify.com/CVE-2023-39953/index.md)","id":"CVE-2023-39953","markdown":"https://insights.sbomify.com/CVE-2023-39953/index.md","name":"CVE-2023-39953","record":{"aliases":["GHSA-xx3h-v363-q36j"],"analysis":{"component_type":"cms_plugin","fix_type":"patch","impacts":["account_takeover","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Nextcloud OIDC plugin","requires_auth":"none","summary":"Attackers can bypass authentication via man-in-the-middle attacks due to missing issuer verification in the Nextcloud OIDC plugin.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"user_oidc","vendor":"nextcloud"}],"cvss":{"score":4.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-303","name":"Incorrect Implementation of Authentication Algorithm"}],"description":"user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"Issuer not verified from obtained token in user_oidc","id":"CVE-2023-39953","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2023"},"n_packages":0,"n_references":3,"next":{"headline":"user_oidc app stores client secret unencrypted in database","id":"CVE-2023-39954"},"packages":[],"prev":{"headline":"Advanced permissions not respected when copying entire group folders","id":"CVE-2023-39952"},"products":["security-advisories"],"published":"2023-08-10","related":[{"cvss_score":8,"headline":"Nextcloud user_oidc app is missing brute force protection","id":"CVE-2023-32074","kev_date_added":null,"published":"2023-05-25"},{"cvss_score":6.3,"headline":"Nextcloud user_oidc app's ID4me feature is available even when disabled","id":"CVE-2024-37312","kev_date_added":null,"published":"2024-06-14"},{"cvss_score":5.4,"headline":"Nextcloud user_oidc's ID4me does not validate signature or expiration","id":"CVE-2024-37886","kev_date_added":null,"published":"2024-06-14"},{"cvss_score":4.8,"headline":"CSRF protection on user_oidc login returned the expected token in case of an error","id":"CVE-2023-28848","kev_date_added":null,"published":"2023-04-04"},{"cvss_score":4.6,"headline":"Nextcloud: Wrong condition in the User OIDC app's LdapService allowed deleted LDAP users to authenticate","id":"CVE-2026-45284","kev_date_added":null,"published":"2026-06-01"},{"cvss_score":3.8,"headline":"user_oidc app stores client secret unencrypted in database","id":"CVE-2023-39954","kev_date_added":null,"published":"2023-08-10"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2024-10-03","vendors":["nextcloud"]},"summary":"Attackers can bypass authentication via man-in-the-middle attacks due to missing issuer verification in the Nextcloud OIDC plugin.","url":"https://insights.sbomify.com/CVE-2023-39953/"}