{"answers":{"affected":"It affects 2 products.","exploited":"There is no known exploitation of CVE-2020-16120 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2020-16120 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 10 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2020-16120 and fix it if it is affected.\n\nWhat it is: CVE-2020-16120 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 10 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2020-16120 in the wild and no public exploit code.\n\nAffected product: Canonical Ubuntu Linux. 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-2020-16120/ (Markdown: https://insights.sbomify.com/CVE-2020-16120/index.md)","id":"CVE-2020-16120","markdown":"https://insights.sbomify.com/CVE-2020-16120/index.md","name":"CVE-2020-16120","record":{"aliases":["AZL-6522","DEBIAN-CVE-2020-16120","GHSA-q6jw-34cj-733v","UBUNTU-CVE-2020-16120"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["privilege_escalation","data_read"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"none","summary":"Unprivileged users can read restricted files via overlayfs copy-up in user namespaces, requiring unprivileged user namespaces to be enabled.","user_interaction":"not_required","vuln_class":"privilege_escalation"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"canonical","cpe":[{"product":"ubuntu_linux","vendor":"canonical"},{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.1,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-266","name":"Incorrect Privilege Assignment"}],"description":"Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (\"ovl: stack file ops\"). This was fixed in kernel version 5.8 by commits 56230d9 (\"ovl: verify permissions in ovl_path_open()\"), 48bd024 (\"ovl: switch to mounter creds in readdir\") and 05acefb (\"ovl: check permission to open real file\"). Additionally, commits 130fdbc (\"ovl: pass correct flags for opening real directory\") and 292f902 (\"ovl: call secutiry hook in ovl_real_ioctl()\") in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da (\"ovl: do not fail because of O_NOATIMEi\") in kernel 5.11.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Unprivileged overlay + shiftfs read access","id":"CVE-2020-16120","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"canonical:ubuntu_linux","products":["canonical:ubuntu_linux","linux:linux_kernel"],"type":"privilege_escalation","year":"2020"},"n_packages":0,"n_references":11,"next":{"headline":"PackageKit error messages leak presence and mimetype of files to unprivileged users","id":"CVE-2020-16121"},"packages":[],"prev":{"headline":"DCCP CCID structure use-after-free","id":"CVE-2020-16119"},"products":["Linux kernel"],"published":"2021-02-10","related":[{"cvss_score":9.8,"headline":"SaltStack Salt Authentication Bypass","id":"CVE-2020-11651","kev_date_added":"2021-11-03","published":"2020-04-30"},{"cvss_score":9.8,"headline":"OpenSMTPD Remote Code Execution","id":"CVE-2020-7247","kev_date_added":"2022-03-25","published":"2020-01-29"},{"cvss_score":9.8,"headline":"Exim Out-of-bounds Write","id":"CVE-2019-16928","kev_date_added":"2022-03-03","published":"2019-09-27"},{"cvss_score":9.8,"headline":"Exim Buffer Overflow","id":"CVE-2018-6789","kev_date_added":"2021-11-03","published":"2018-02-08"},{"cvss_score":9.8,"headline":"Oracle Java SE and Java SE Embedded Remote Code Execution","id":"CVE-2015-2590","kev_date_added":"2022-03-03","published":"2015-07-16"},{"cvss_score":9.8,"headline":"Oracle JRE Remote Code Execution","id":"CVE-2013-0422","kev_date_added":"2022-05-25","published":"2013-01-10"},{"cvss_score":9.8,"headline":"Oracle Java SE Runtime Environment (JRE) Arbitrary Code Execution","id":"CVE-2011-3544","kev_date_added":"2022-03-03","published":"2011-10-19"}],"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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-09-16","vendors":["Linux kernel"]},"summary":"Unprivileged users can read restricted files via overlayfs copy-up in user namespaces, requiring unprivileged user namespaces to be enabled.","url":"https://insights.sbomify.com/CVE-2020-16120/"}