{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-99191 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-99191 is a vulnerability in Linux, published on 28 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-99191 and fix it if it is affected.\n\nWhat it is: CVE-2026-99191 is a vulnerability in Linux, published on 28 Oct 2026. \nExploitation: There is no known exploitation of CVE-2026-99191 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-99191/ (Markdown: https://insights.sbomify.com/CVE-2026-99191/index.md)","id":"CVE-2026-99191","markdown":"https://insights.sbomify.com/CVE-2026-99191/index.md","name":"CVE-2026-99191","record":{"aliases":["AZL-111356","BELL-CVE-2026-99191","DEBIAN-CVE-2026-99191","GHSA-4qqv-fgh9-mg86","UBUNTU-CVE-2026-99191"],"analysis":null,"analysis_generated_by":null,"assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncalipso: keep BIG TCP payload_len in calipso_skbuff_setattr()\n\ncalipso_skbuff_setattr() adjusts payload_len by the length of the\noption it inserts or resizes:\n\n\tpayload = ntohs(ip6_hdr-\u003epayload_len);\n\tip6_hdr-\u003epayload_len = htons(payload + len_delta);\n\nGRO can build BIG TCP packets larger than IPV6_MAXPLEN, and stores\npayload_len == 0 for them; ipv6_payload_len() then falls back to\nskb-\u003elen.  For such a packet forwarded to a destination mapped to\nCALIPSO, the code above writes len_delta (or 65536 + len_delta when\nshrinking) into payload_len, and ipv6_payload_len() no longer falls\nback to skb-\u003elen.  nf_tables, conntrack and sch_cake rely on it.\n\nThe same arithmetic also wraps when a packet grows past IPV6_MAXPLEN,\nand a BIG TCP packet that shrinks below IPV6_MAXPLEN should get its\nreal length back.\n\nSet payload_len from the skb length with ipv6_set_payload_len(), which\nstores 0 above IPV6_MAXPLEN and the real length otherwise, as\nipv6_gro_complete() does.  The network header was just reset to\nskb-\u003edata, so skb-\u003elen - sizeof(*ip6_hdr) is the payload length.\n\nTested on one kernel (arm64, QEMU) with SELinux permissive, a minimal\nmdp-generated policy (network_peer_controls=1), \"netlabelctl calipso\nadd pass doi:16\" and a NetLabel mapping of fd00:2::/64 to CALIPSO\nDOI 16.  calipso_skbuff_setattr() was called through\nnetlbl_skbuff_setattr() from a test-only debugfs hook (not part of\nthis patch) adding a level-only label; payload_len after the call:\n\n  case                         before fix   after fix   real length\n  1000, unlabeled                    1016        1016          1016\n  70000 GSO, payload_len 0             16           0         70016\n  65530 GSO, grows past MAXPLEN        10           0         65546\n  65540 GSO with a 24 byte hop\n  header, shrinks below MAXPLEN     65528       65532         65532\n  1000 with a 24 byte hop header      992         992           992\n\n(0 means ipv6_payload_len() returns the real length.)  On the forward\npath, with a client injecting unlabeled UDP through a router to a\nserver, the router adds the CALIPSO option and the server delivers all\ndatagrams (Udp6InDatagrams 5, Ip6InTruncatedPkts 0) with this patch.","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":"calipso: keep BIG TCP payload_len in calipso_skbuff_setattr()","id":"CVE-2026-99191","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":null,"year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"net: bcmgenet: unshare the skb before writing the control block","id":"CVE-2026-99192"},"packages":[],"prev":{"headline":"gpiolib: fix memory leak in gpiod_set_array_value_complex() on error paths","id":"CVE-2026-99190"},"products":["Linux"],"published":"2026-10-28","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-28","vendors":["Linux"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-99191/"}