{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2020-36789 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2020-36789 is a medium-severity vulnerability in Linux kernel, published on 17 Apr 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-2020-36789 and fix it if it is affected.\n\nWhat it is: CVE-2020-36789 is a medium-severity vulnerability in Linux kernel, published on 17 Apr 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-2020-36789 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-2020-36789/ (Markdown: https://insights.sbomify.com/CVE-2020-36789/index.md)","id":"CVE-2020-36789","markdown":"https://insights.sbomify.com/CVE-2020-36789/index.md","name":"CVE-2020-36789","record":{"aliases":["DEBIAN-CVE-2020-36789","GHSA-5974-c6r6-2pv9","UBUNTU-CVE-2020-36789"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel CAN stack","requires_auth":"low_privilege","summary":"A NULL pointer dereference in the Linux kernel CAN stack can cause a system crash when processing network congestion in hardware IRQ context.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context\n\nIf a driver calls can_get_echo_skb() during a hardware IRQ (which is often, but\nnot always, the case), the 'WARN_ON(in_irq)' in\nnet/core/skbuff.c#skb_release_head_state() might be triggered, under network\ncongestion circumstances, together with the potential risk of a NULL pointer\ndereference.\n\nThe root cause of this issue is the call to kfree_skb() instead of\ndev_kfree_skb_irq() in net/core/dev.c#enqueue_to_backlog().\n\nThis patch prevents the skb to be freed within the call to netif_rx() by\nincrementing its reference count with skb_get(). The skb is finally freed by\none of the in-irq-context safe functions: dev_consume_skb_any() or\ndev_kfree_skb_any(). The \"any\" version is used because some drivers might call\ncan_get_echo_skb() in a normal context.\n\nThe reason for this issue to occur is that initially, in the core network\nstack, loopback skb were not supposed to be received in hardware IRQ context.\nThe CAN stack is an exeption.\n\nThis bug was previously reported back in 2017 in [1] but the proposed patch\nnever got accepted.\n\nWhile [1] directly modifies net/core/dev.c, we try to propose here a\nsmoother modification local to CAN network stack (the assumption\nbehind is that only CAN devices are affected by this issue).\n\n[1] http://lore.kernel.org/r/57a3ffb6-3309-3ad5-5a34-e93c3fe3614d@cetitec.com","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":"can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context","id":"CVE-2020-36789","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2020"},"n_packages":0,"n_references":7,"next":{"headline":"nvmet: fix a memory leak","id":"CVE-2020-36790"},"packages":[],"prev":{"headline":"drm/nouveau: avoid a use-after-free when BO init fails","id":"CVE-2020-36788"},"products":["Linux"],"published":"2025-04-17","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":"partial"},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A NULL pointer dereference in the Linux kernel CAN stack can cause a system crash when processing network congestion in hardware IRQ context.","url":"https://insights.sbomify.com/CVE-2020-36789/"}