{"answers":{"affected":"It affects 2 products.","exploited":"There is no known exploitation of CVE-2025-40300 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40300 is a medium-severity vulnerability in Debian Debian Linux, published on 11 Sep 2025. 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-2025-40300 and fix it if it is affected.\n\nWhat it is: CVE-2025-40300 is a medium-severity vulnerability in Debian Debian Linux, published on 11 Sep 2025. 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-2025-40300 in the wild and no public exploit code.\n\nAffected product: Debian Debian 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-2025-40300/ (Markdown: https://insights.sbomify.com/CVE-2025-40300/index.md)","id":"CVE-2025-40300","markdown":"https://insights.sbomify.com/CVE-2025-40300/index.md","name":"CVE-2025-40300","record":{"aliases":["AZL-67238","AZL-74763","BELL-CVE-2025-40300","DEBIAN-CVE-2025-40300","GHSA-x8qw-46ww-c957","ROOT-OS-DEBIAN-11-CVE-2025-40300","ROOT-OS-DEBIAN-12-CVE-2025-40300","ROOT-OS-DEBIAN-13-CVE-2025-40300","ROOT-OS-UBUNTU-2204-CVE-2025-40300","ROOT-OS-UBUNTU-2404-CVE-2025-40300","UBUNTU-CVE-2025-40300","USN-7860-1","USN-7860-2","USN-7860-3","USN-7860-4","USN-7860-5","USN-7862-1","USN-7862-2","USN-7862-3","openSUSE-SU-2025:15553-1"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["data_read"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A malicious guest VM can leak sensitive data from the host userspace hypervisor via branch predictor side-channels, requiring kernel patches to mitigate.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/vmscape: Add conditional IBPB mitigation\n\nVMSCAPE is a vulnerability that exploits insufficient branch predictor\nisolation between a guest and a userspace hypervisor (like QEMU). Existing\nmitigations already protect kernel/KVM from a malicious guest. Userspace\ncan additionally be protected by flushing the branch predictors after a\nVMexit.\n\nSince it is the userspace that consumes the poisoned branch predictors,\nconditionally issue an IBPB after a VMexit and before returning to\nuserspace. Workloads that frequently switch between hypervisor and\nuserspace will incur the most overhead from the new IBPB.\n\nThis new IBPB is not integrated with the existing IBPB sites. For\ninstance, a task can use the existing speculation control prctl() to\nget an IBPB at context switch time. With this implementation, the\nIBPB is doubled up: one at context switch and another before running\nuserspace.\n\nThe intent is to integrate and optimize these cases post-embargo.\n\n[ dhansen: elaborate on suboptimal IBPB solution ]","ecosystems":["openSUSE:Tumbleweed"],"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":"x86/vmscape: Add conditional IBPB mitigation","id":"CVE-2025-40300","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"debian:debian_linux","products":["debian:debian_linux","linux:linux_kernel"],"type":"information_disclosure","year":"2025"},"n_packages":1,"n_references":13,"next":{"headline":"Bluetooth: hci_event: validate skb length for unknown CC opcode","id":"CVE-2025-40301"},"packages":[{"ecosystem":"openSUSE:Tumbleweed","fixed":["6.16.7-1.1"],"introduced":["0"],"last_affected":[],"package":"kernel-source","purl":"pkg:rpm/opensuse/kernel-source\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2025:15553-1"}],"prev":{"headline":"gve: Implement gettimex64 with -EOPNOTSUPP","id":"CVE-2025-40299"},"products":["Linux"],"published":"2025-09-11","related":[{"cvss_score":10,"headline":"ProFTPD Improper Access Control","id":"CVE-2015-3306","kev_date_added":"2026-10-08","published":"2015-05-18"},{"cvss_score":9.9,"headline":"RoundCube Webmail Deserialization of Untrusted Data","id":"CVE-2025-49113","kev_date_added":"2026-02-20","published":"2025-06-02"},{"cvss_score":9.8,"headline":"GNU InetUtils Argument Injection","id":"CVE-2026-24061","kev_date_added":"2026-01-26","published":"2026-01-21"},{"cvss_score":9.8,"headline":"Linux Kernel Improper Check for Unusual or Exceptional Conditions","id":"CVE-2025-39682","kev_date_added":"2026-09-18","published":"2025-09-05"},{"cvss_score":9.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2024-9680","kev_date_added":"2024-10-15","published":"2024-10-09"},{"cvss_score":9.8,"headline":"RARLAB UnRAR Directory Traversal","id":"CVE-2022-30333","kev_date_added":"2022-08-09","published":"2022-05-09"},{"cvss_score":9.8,"headline":"Roundcube Webmail SQL Injection","id":"CVE-2021-44026","kev_date_added":"2023-06-22","published":"2021-11-19"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"A malicious guest VM can leak sensitive data from the host userspace hypervisor via branch predictor side-channels, requiring kernel patches to mitigate.","url":"https://insights.sbomify.com/CVE-2025-40300/"}