{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-89542 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-89542 is a critical vulnerability in Linux, published on 11 Sep 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-2026-89542 and fix it if it is affected.\n\nWhat it is: CVE-2026-89542 is a critical vulnerability in Linux, published on 11 Sep 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-2026-89542 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-2026-89542/ (Markdown: https://insights.sbomify.com/CVE-2026-89542/index.md)","id":"CVE-2026-89542","markdown":"https://insights.sbomify.com/CVE-2026-89542/index.md","name":"CVE-2026-89542","record":{"aliases":["AZL-100515","BELL-CVE-2026-89542","DEBIAN-CVE-2026-89542","GHSA-h928-qw5v-x6vj","UBUNTU-CVE-2026-89542"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel SUNRPC","requires_auth":"none","summary":"A missing length check in the Linux kernel's SUNRPC GSS-KRB5 unwrap function allows out-of-bounds reads and integer overflows, potentially leading to system crashes or code execution.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":9.8,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_krb5_unwrap_v2 against short tokens\n\ngss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and\nptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN\n(16) bytes long, and its rotate_left() helper passes buf-\u003elen - base\nto xdr_buf_subsegment() without verifying that base \u003c= buf-\u003elen. When\na caller hands in a sub-16-byte token, or a token whose declared len\nleaves base past the end of the buffer, three distinct failures follow:\n\n    gss_krb5_unwrap_v2(offset, len, buf)\n      ptr = buf-\u003ehead[0].iov_base + offset\n      ec  = *(ptr + 4)              /* OOB read on short head */\n      rrc = *(ptr + 6)              /* OOB read on short head */\n      rotate_left(offset + 16, buf, rrc)\n        xdr_buf_subsegment(buf, \u0026subbuf,\n                           base, buf-\u003elen - base)   /* u32 wrap when base \u003e len */\n        _rotate_left(\u0026subbuf, shift)\n          shift %= buf-\u003elen         /* divide-by-zero when base == len */\n\nAfter decryption, the cleanup arithmetic has the same shape:\n\n    movelen = min_t(unsigned int, buf-\u003ehead[0].iov_len, len);\n    movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;\n    BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen \u003e\n                                            buf-\u003ehead[0].iov_len);\n\nThe BUG_ON re-adds the value just subtracted, so it reduces to\nmin(A, B) \u003e A and is permanently false; it cannot catch the unsigned\nunderflow of movelen, which then drives a ~UINT_MAX-byte memmove().\n\nAdd four defense-in-depth guards inside the unwrap core so it is safe\nregardless of what its callers validate:\n\n  - reject tokens with len - offset \u003c GSS_KRB5_TOK_HDR_LEN before\n    touching ptr+4/ptr+6;\n  - bail from rotate_left() when buf-\u003elen \u003c= base, covering both the\n    underflow and zero-length cases;\n  - return early from _rotate_left() when buf-\u003elen is zero, so the\n    shift %= buf-\u003elen modulo cannot fault;\n  - replace the dead BUG_ON with a live check that returns\n    GSS_S_DEFECTIVE_TOKEN before the movelen subtraction.","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":"SUNRPC: harden gss_krb5_unwrap_v2 against short tokens","id":"CVE-2026-89542","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"integer_overflow","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir","id":"CVE-2026-89543"},"packages":[],"prev":{"headline":"SUNRPC: harden gss_unwrap_resp_priv length checks","id":"CVE-2026-89541"},"products":["Linux"],"published":"2026-09-11","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A missing length check in the Linux kernel's SUNRPC GSS-KRB5 unwrap function allows out-of-bounds reads and integer overflows, potentially leading to system crashes or code execution.","url":"https://insights.sbomify.com/CVE-2026-89542/"}