{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-53240 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-53240 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-53240 and fix it if it is affected.\n\nWhat it is: CVE-2026-53240 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-53240 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-2026-53240/ (Markdown: https://insights.sbomify.com/CVE-2026-53240/index.md)","id":"CVE-2026-53240","markdown":"https://insights.sbomify.com/CVE-2026-53240/index.md","name":"CVE-2026-53240","record":{"aliases":["BELL-CVE-2026-53240","DEBIAN-CVE-2026-53240","GHSA-5m64-3x43-vxjx","UBUNTU-CVE-2026-53240"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free in the Linux kernel's xfrm iptfs module allows attackers to execute arbitrary code or cause a denial of service via race conditions.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":8.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: fix use-after-free on first_skb in __input_process_payload\n\n__input_process_payload() stores first_skb into xtfs-\u003era_newskb under\ndrop_lock when starting partial reassembly, then unlocks and breaks out\nof the processing loop. The post-loop check reads xtfs-\u003era_newskb\nwithout the lock to decide whether first_skb is still owned:\n\n    if (first_skb \u0026\u0026 first_iplen \u0026\u0026 !defer \u0026\u0026 first_skb != xtfs-\u003era_newskb)\n\nBetween spin_unlock and this read, a concurrent CPU running\niptfs_reassem_cont() (or the drop_timer hrtimer) can complete\nreassembly, NULL xtfs-\u003era_newskb, and free the skb. The check then\nevaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb\noperate on the freed skb — a use-after-free in skbuff_head_cache.\n\nReplace the unlocked read with a local bool that records whether\nfirst_skb was handed to the reassembly state in the current call. The\nflag is set after the existing spin_unlock, before the break, using the\npointer equality that is stable at that point (first_skb == skb iff\nfirst_skb was stored in ra_newskb).","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":"xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload","id":"CVE-2026-53240","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"ALSA: seq: dummy: fix UMP event stack overread","id":"CVE-2026-53241"},"packages":[],"prev":{"headline":"xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()","id":"CVE-2026-53239"},"products":["Linux"],"published":"2026-06-25","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel's xfrm iptfs module allows attackers to execute arbitrary code or cause a denial of service via race conditions.","url":"https://insights.sbomify.com/CVE-2026-53240/"}