{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-28689 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-28689 is a medium-severity vulnerability in Xen Xen, published on 11 Jun 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-2021-28689 and fix it if it is affected.\n\nWhat it is: CVE-2021-28689 is a medium-severity vulnerability in Xen Xen, published on 11 Jun 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-2021-28689 in the wild and no public exploit code.\n\nAffected product: Xen Xen. 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-2021-28689/ (Markdown: https://insights.sbomify.com/CVE-2021-28689/index.md)","id":"CVE-2021-28689","markdown":"https://insights.sbomify.com/CVE-2021-28689/index.md","name":"CVE-2021-28689","record":{"aliases":["DEBIAN-CVE-2021-28689","GHSA-45vh-fhgx-cr2p","SUSE-SU-2021:1648-1","UBUNTU-CVE-2021-28689"],"analysis":{"component_type":"operating_system","fix_type":"patch","impacts":["data_read"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Xen hypervisor","requires_auth":"low_privilege","summary":"Attackers can exploit speculative execution side channels in 32-bit PV guests to read sensitive data from ring 0 due to IBRS limitations.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"XEN","cpe":[{"product":"xen","vendor":"xen"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-212","name":"Improper Removal of Sensitive Information Before Storage or Transfer"}],"description":"x86: Speculative vulnerabilities with bare (non-shim) 32-bit PV guests 32-bit x86 PV guest kernels run in ring 1. At the time when Xen was developed, this area of the i386 architecture was rarely used, which is why Xen was able to use it to implement paravirtualisation, Xen's novel approach to virtualization. In AMD64, Xen had to use a different implementation approach, so Xen does not use ring 1 to support 64-bit guests. With the focus now being on 64-bit systems, and the availability of explicit hardware support for virtualization, fixing speculation issues in ring 1 is not a priority for processor companies. Indirect Branch Restricted Speculation (IBRS) is an architectural x86 extension put together to combat speculative execution sidechannel attacks, including Spectre v2. It was retrofitted in microcode to existing CPUs. For more details on Spectre v2, see: http://xenbits.xen.org/xsa/advisory-254.html However, IBRS does not architecturally protect ring 0 from predictions learnt in ring 1. For more details, see: https://software.intel.com/security-software-guidance/deep-dives/deep-dive-indirect-branch-restricted-speculation Similar situations may exist with other mitigations for other kinds of speculative execution attacks. The situation is quite likely to be similar for speculative execution attacks which have yet to be discovered, disclosed, or mitigated.","ecosystems":["SUSE:Linux Enterprise Server 12 SP4-LTSS","SUSE:Linux Enterprise Server for SAP Applications 12 SP4","SUSE:OpenStack Cloud 9","SUSE:OpenStack Cloud Crowbar 9"],"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":"Information disclosure in Xen","id":"CVE-2021-28689","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"xen:xen","products":["xen:xen"],"type":"information_disclosure","year":"2021"},"n_packages":4,"n_references":1,"next":{"headline":"Security feature bypass in xen","id":"CVE-2021-28690"},"packages":[{"ecosystem":"SUSE:Linux Enterprise Server 12 SP4-LTSS","fixed":["4.11.4_18-2.54.1"],"introduced":["0"],"last_affected":[],"package":"xen","purl":"pkg:rpm/suse/xen\u0026distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSS","source":"SUSE-SU-2021:1648-1"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12 SP4","fixed":["4.11.4_18-2.54.1"],"introduced":["0"],"last_affected":[],"package":"xen","purl":"pkg:rpm/suse/xen\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4","source":"SUSE-SU-2021:1648-1"},{"ecosystem":"SUSE:OpenStack Cloud 9","fixed":["4.11.4_18-2.54.1"],"introduced":["0"],"last_affected":[],"package":"xen","purl":"pkg:rpm/suse/xen\u0026distro=SUSE%20OpenStack%20Cloud%209","source":"SUSE-SU-2021:1648-1"},{"ecosystem":"SUSE:OpenStack Cloud Crowbar 9","fixed":["4.11.4_18-2.54.1"],"introduced":["0"],"last_affected":[],"package":"xen","purl":"pkg:rpm/suse/xen\u0026distro=SUSE%20OpenStack%20Cloud%20Crowbar%209","source":"SUSE-SU-2021:1648-1"}],"prev":{"headline":"Memory corruption in Linux","id":"CVE-2021-28688"},"products":["Xen"],"published":"2021-06-11","related":[{"cvss_score":10,"headline":"Privilege escalation in n/a","id":"CVE-2017-10912","kev_date_added":null,"published":"2017-07-05"},{"cvss_score":10,"headline":"Memory corruption in n/a","id":"CVE-2017-10918","kev_date_added":null,"published":"2017-07-05"},{"cvss_score":10,"headline":"Memory corruption in n/a","id":"CVE-2017-10920","kev_date_added":null,"published":"2017-07-05"},{"cvss_score":10,"headline":"Memory corruption in n/a","id":"CVE-2017-10921","kev_date_added":null,"published":"2017-07-05"},{"cvss_score":9.8,"headline":"Mutiple vulnerabilities in the Viridian interface","id":"CVE-2025-27466","kev_date_added":null,"published":"2025-09-11"},{"cvss_score":9.8,"headline":"Mutiple vulnerabilities in the Viridian interface","id":"CVE-2025-58142","kev_date_added":null,"published":"2025-09-11"},{"cvss_score":9.8,"headline":"Mutiple vulnerabilities in the Viridian interface","id":"CVE-2025-58143","kev_date_added":null,"published":"2025-09-11"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"SUSE"},{"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":"2024-08-03","vendors":["Xen"]},"summary":"Attackers can exploit speculative execution side channels in 32-bit PV guests to read sensitive data from ring 0 due to IBRS limitations.","url":"https://insights.sbomify.com/CVE-2021-28689/"}