{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-4247 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-4247 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-4247 is a high-severity denial of service vulnerability in Freebsd Freebsd, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-4247 and fix it if it is affected.\n\nWhat it is: CVE-2026-4247 is a high-severity denial of service vulnerability in Freebsd Freebsd, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-4247 in the wild and no public exploit code.\n\nAffected product: Freebsd Freebsd. 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-2026-4247/ (Markdown: https://insights.sbomify.com/CVE-2026-4247/index.md)","id":"CVE-2026-4247","markdown":"https://insights.sbomify.com/CVE-2026-4247/index.md","name":"CVE-2026-4247","record":{"aliases":["GHSA-374j-38xh-4wr2"],"analysis":{"component_type":"operating_system","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"FreeBSD kernel","requires_auth":"none","summary":"Remote attackers can cause a denial of service on FreeBSD systems by leaking memory through crafted TCP packets that trigger a challenge ACK logic error.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"freebsd","cpe":[{"product":"freebsd","vendor":"freebsd"}],"cvss":{"score":7.5,"severity":"high","source":"cisa-adp","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-401","name":"Missing Release of Memory after Effective Lifetime"}],"description":"When a challenge ACK is to be sent tcp_respond() constructs and sends the challenge ACK and consumes the mbuf that is passed in.  When no challenge ACK should be sent the function returns and leaks the mbuf.\n\nIf an attacker is either on path with an established TCP connection, or can themselves establish a TCP connection, to an affected FreeBSD machine, they can easily craft and send packets which meet the challenge ACK criteria and cause the FreeBSD host to leak an mbuf for each crafted packet in excess of the configured rate limit settings i.e. with default settings, crafted packets in excess of the first 5 sent within a 1s period will leak an mbuf.\n\nTechnically, off-path attackers can also exploit this problem by guessing the IP addresses, TCP port numbers and in some cases the sequence numbers of established connections and spoofing packets towards a FreeBSD machine, but this is harder to do effectively.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"TCP: remotely exploitable DoS vector (mbuf leak)","id":"CVE-2026-4247","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"freebsd:freebsd","products":["freebsd:freebsd"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Information disclosure in Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction \u0026 Membership Plugin","id":"CVE-2026-4248"},"packages":[],"prev":{"headline":"ElementsKit Pro \u003c= 4.10.1 - Unauthenticated Stored Cross-Site Scripting via 's' Parameter","id":"CVE-2026-4246"},"products":["FreeBSD"],"published":"2026-03-26","related":[{"cvss_score":10,"headline":"Memory corruption in FreeBSD","id":"CVE-2018-17160","kev_date_added":null,"published":"2018-12-04"},{"cvss_score":10,"headline":"Memory corruption in n/a","id":"CVE-2014-3954","kev_date_added":null,"published":"2014-10-27"},{"cvss_score":10,"headline":"Memory corruption in n/a","id":"CVE-2006-4304","kev_date_added":null,"published":"2006-08-24"},{"cvss_score":10,"headline":"Integer overflow in n/a","id":"CVE-2006-0226","kev_date_added":null,"published":"2006-01-19"},{"cvss_score":10,"headline":"Denial of service in n/a","id":"CVE-2004-0002","kev_date_added":null,"published":"2004-02-03"},{"cvss_score":10,"headline":"Security feature bypass in n/a","id":"CVE-2001-0969","kev_date_added":null,"published":"2002-03-09"},{"cvss_score":10,"headline":"Denial of service in n/a","id":"CVE-2001-0388","kev_date_added":null,"published":"2001-09-18"}],"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-03-26","vendors":["FreeBSD"]},"summary":"Remote attackers can cause a denial of service on FreeBSD systems by leaking memory through crafted TCP packets that trigger a challenge ACK logic error.","url":"https://insights.sbomify.com/CVE-2026-4247/"}