{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-31788 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-31788 is a high-severity vulnerability in Linux kernel, published on 25 Mar 2026. 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-2026-31788 and fix it if it is affected.\n\nWhat it is: CVE-2026-31788 is a high-severity vulnerability in Linux kernel, published on 25 Mar 2026. 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-2026-31788 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2026-31788/ (Markdown: https://insights.sbomify.com/CVE-2026-31788/index.md)","id":"CVE-2026-31788","markdown":"https://insights.sbomify.com/CVE-2026-31788/index.md","name":"CVE-2026-31788","record":{"aliases":["BELL-CVE-2026-31788","DEBIAN-CVE-2026-31788","GHSA-q397-v647-xvh6","ROOT-OS-DEBIAN-11-CVE-2026-31788","ROOT-OS-DEBIAN-12-CVE-2026-31788","ROOT-OS-DEBIAN-13-CVE-2026-31788","ROOT-OS-UBUNTU-2204-CVE-2026-31788","ROOT-OS-UBUNTU-2404-CVE-2026-31788","UBUNTU-CVE-2026-31788"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["privilege_escalation","security_bypass"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel Xen driver","requires_auth":"high_privilege","summary":"A local attacker with root access in an unprivileged Xen guest can bypass Secure Boot restrictions by modifying kernel memory via the privcmd driver.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":8.2,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-862","name":"Missing Authorization"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxen/privcmd: restrict usage in unprivileged domU\n\nThe Xen privcmd driver allows to issue arbitrary hypercalls from\nuser space processes. This is normally no problem, as access is\nusually limited to root and the hypervisor will deny any hypercalls\naffecting other domains.\n\nIn case the guest is booted using secure boot, however, the privcmd\ndriver would be enabling a root user process to modify e.g. kernel\nmemory contents, thus breaking the secure boot feature.\n\nThe only known case where an unprivileged domU is really needing to\nuse the privcmd driver is the case when it is acting as the device\nmodel for another guest. In this case all hypercalls issued via the\nprivcmd driver will target that other guest.\n\nFortunately the privcmd driver can already be locked down to allow\nonly hypercalls targeting a specific domain, but this mode can be\nactivated from user land only today.\n\nThe target domain can be obtained from Xenstore, so when not running\nin dom0 restrict the privcmd driver to that target domain from the\nbeginning, resolving the potential problem of breaking secure boot.\n\nThis is XSA-482\n\n---\nV2:\n- defer reading from Xenstore if Xenstore isn't ready yet (Jan Beulich)\n- wait in open() if target domain isn't known yet\n- issue message in case no target domain found (Jan Beulich)","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":"xen/privcmd: restrict usage in unprivileged domU","id":"CVE-2026-31788","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"security_feature_bypass","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"Heap Buffer Overflow in Hexadecimal Conversion","id":"CVE-2026-31789"},"packages":[],"prev":{"headline":"xen/privcmd: fix double free via VMA splitting","id":"CVE-2026-31787"},"products":["Linux"],"published":"2026-03-25","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"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":"total"},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A local attacker with root access in an unprivileged Xen guest can bypass Secure Boot restrictions by modifying kernel memory via the privcmd driver.","url":"https://insights.sbomify.com/CVE-2026-31788/"}