{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-38463 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-38463 is a high-severity vulnerability in Linux kernel, published on 25 Jul 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-2025-38463 and fix it if it is affected.\n\nWhat it is: CVE-2025-38463 is a high-severity vulnerability in Linux kernel, published on 25 Jul 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-2025-38463 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-2025-38463/ (Markdown: https://insights.sbomify.com/CVE-2025-38463/index.md)","id":"CVE-2025-38463","markdown":"https://insights.sbomify.com/CVE-2025-38463/index.md","name":"CVE-2025-38463","record":{"aliases":["AZL-65774","BELL-CVE-2025-38463","DEBIAN-CVE-2025-38463","GHSA-7fhq-j7h5-cjxg","ROOT-OS-UBUNTU-2404-CVE-2025-38463","UBUNTU-CVE-2025-38463"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A signedness error in Linux kernel TCP code allows integer overflow, potentially leading to denial of service.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-191","name":"Integer Underflow (Wrap or Wraparound)"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: Correct signedness in skb remaining space calculation\n\nSyzkaller reported a bug [1] where sk-\u003esk_forward_alloc can overflow.\n\nWhen we send data, if an skb exists at the tail of the write queue, the\nkernel will attempt to append the new data to that skb. However, the code\nthat checks for available space in the skb is flawed:\n'''\ncopy = size_goal - skb-\u003elen\n'''\n\nThe types of the variables involved are:\n'''\ncopy: ssize_t (s64 on 64-bit systems)\nsize_goal: int\nskb-\u003elen: unsigned int\n'''\n\nDue to C's type promotion rules, the signed size_goal is converted to an\nunsigned int to match skb-\u003elen before the subtraction. The result is an\nunsigned int.\n\nWhen this unsigned int result is then assigned to the s64 copy variable,\nit is zero-extended, preserving its non-negative value. Consequently, copy\nis always \u003e= 0.\n\nAssume we are sending 2GB of data and size_goal has been adjusted to a\nvalue smaller than skb-\u003elen. The subtraction will result in copy holding a\nvery large positive integer. In the subsequent logic, this large value is\nused to update sk-\u003esk_forward_alloc, which can easily cause it to overflow.\n\nThe syzkaller reproducer uses TCP_REPAIR to reliably create this\ncondition. However, this can also occur in real-world scenarios. The\ntcp_bound_to_half_wnd() function can also reduce size_goal to a small\nvalue. This would cause the subsequent tcp_wmem_schedule() to set\nsk-\u003esk_forward_alloc to a value close to INT_MAX. Further memory\nallocation requests would then cause sk_forward_alloc to wrap around and\nbecome negative.\n\n[1]: https://syzkaller.appspot.com/bug?extid=de6565462ab540f50e47","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":"tcp: Correct signedness in skb remaining space calculation","id":"CVE-2025-38463","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"integer_overflow","year":"2025"},"n_packages":0,"n_references":4,"next":{"headline":"tipc: Fix use-after-free in tipc_conn_close().","id":"CVE-2025-38464"},"packages":[],"prev":{"headline":"vsock: Fix transport_{g2h,h2g} TOCTOU","id":"CVE-2025-38462"},"products":["Linux"],"published":"2025-07-25","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 signedness error in Linux kernel TCP code allows integer overflow, potentially leading to denial of service.","url":"https://insights.sbomify.com/CVE-2025-38463/"}