{"api_version":"1","generated_at":"2026-05-31T07:54:57+00:00","cve":"CVE-2026-46086","urls":{"html":"https://cve.report/CVE-2026-46086","api":"https://cve.report/api/cve/CVE-2026-46086.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-46086","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-46086"},"summary":{"title":"net: bridge: use a stable FDB dst snapshot in RCU readers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: use a stable FDB dst snapshot in RCU readers\n\nLocal FDB entries can be rewritten in place by `fdb_delete_local()`, which\nupdates `f->dst` to another port or to `NULL` while keeping the entry\nalive. Several bridge RCU readers inspect `f->dst`, including\n`br_fdb_fillbuf()` through the `brforward_read()` sysfs path.\n\nThese readers currently load `f->dst` multiple times and can therefore\nobserve inconsistent values across the check and later dereference.\nIn `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change\n`f->dst` after the NULL check and before the `port_no` dereference,\nleading to a NULL-ptr-deref.\n\nFix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each\naffected RCU reader and using that snapshot for the rest of the access\nsequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()`\nwith `WRITE_ONCE()` so the readers and writer use matching access patterns.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-27 14:17:30","updated_at":"2026-05-27 14:48:03"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808","name":"https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f","name":"https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110","name":"https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef","name":"https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5","name":"https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-46086","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46086","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 960b589f86c74ce582922fcb996103271081f4de 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 960b589f86c74ce582922fcb996103271081f4de 81af4137a30c4c2dc694dea8cacb180bd66000ef git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 960b589f86c74ce582922fcb996103271081f4de 5424e678f9b304e148cf5dcc047cffc7a56a3bb5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 960b589f86c74ce582922fcb996103271081f4de 9a2d9d4e657b23dc21f24cf139e3aeff0b61341f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 960b589f86c74ce582922fcb996103271081f4de df4601653201de21b487c3e7fffd464790cab808 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.140 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.86 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.27 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.4 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"46086","cve":"CVE-2026-46086","epss":"0.000180000","percentile":"0.051570000","score_date":"2026-05-30","updated_at":"2026-05-31 00:14:03"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/bridge/br_arp_nd_proxy.c","net/bridge/br_fdb.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"0b9e4bbfb7c949151e3acd44ed4aa33614d2e110","status":"affected","version":"960b589f86c74ce582922fcb996103271081f4de","versionType":"git"},{"lessThan":"81af4137a30c4c2dc694dea8cacb180bd66000ef","status":"affected","version":"960b589f86c74ce582922fcb996103271081f4de","versionType":"git"},{"lessThan":"5424e678f9b304e148cf5dcc047cffc7a56a3bb5","status":"affected","version":"960b589f86c74ce582922fcb996103271081f4de","versionType":"git"},{"lessThan":"9a2d9d4e657b23dc21f24cf139e3aeff0b61341f","status":"affected","version":"960b589f86c74ce582922fcb996103271081f4de","versionType":"git"},{"lessThan":"df4601653201de21b487c3e7fffd464790cab808","status":"affected","version":"960b589f86c74ce582922fcb996103271081f4de","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bridge/br_arp_nd_proxy.c","net/bridge/br_fdb.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.14"},{"lessThan":"3.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.140","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.86","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.27","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.140","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.86","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.27","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.4","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1-rc1","versionStartIncluding":"3.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: use a stable FDB dst snapshot in RCU readers\n\nLocal FDB entries can be rewritten in place by `fdb_delete_local()`, which\nupdates `f->dst` to another port or to `NULL` while keeping the entry\nalive. Several bridge RCU readers inspect `f->dst`, including\n`br_fdb_fillbuf()` through the `brforward_read()` sysfs path.\n\nThese readers currently load `f->dst` multiple times and can therefore\nobserve inconsistent values across the check and later dereference.\nIn `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change\n`f->dst` after the NULL check and before the `port_no` dereference,\nleading to a NULL-ptr-deref.\n\nFix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each\naffected RCU reader and using that snapshot for the rest of the access\nsequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()`\nwith `WRITE_ONCE()` so the readers and writer use matching access patterns."}],"providerMetadata":{"dateUpdated":"2026-05-27T12:58:28.137Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110"},{"url":"https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef"},{"url":"https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5"},{"url":"https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f"},{"url":"https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808"}],"title":"net: bridge: use a stable FDB dst snapshot in RCU readers","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-46086","datePublished":"2026-05-27T12:58:28.137Z","dateReserved":"2026-05-13T15:03:33.096Z","dateUpdated":"2026-05-27T12:58:28.137Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 14:17:30","lastModifiedDate":"2026-05-27 14:48:03","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"46086","Ordinal":"1","Title":"net: bridge: use a stable FDB dst snapshot in RCU readers","CVE":"CVE-2026-46086","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"46086","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: use a stable FDB dst snapshot in RCU readers\n\nLocal FDB entries can be rewritten in place by `fdb_delete_local()`, which\nupdates `f->dst` to another port or to `NULL` while keeping the entry\nalive. Several bridge RCU readers inspect `f->dst`, including\n`br_fdb_fillbuf()` through the `brforward_read()` sysfs path.\n\nThese readers currently load `f->dst` multiple times and can therefore\nobserve inconsistent values across the check and later dereference.\nIn `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change\n`f->dst` after the NULL check and before the `port_no` dereference,\nleading to a NULL-ptr-deref.\n\nFix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each\naffected RCU reader and using that snapshot for the rest of the access\nsequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()`\nwith `WRITE_ONCE()` so the readers and writer use matching access patterns.","Type":"Description","Title":"net: bridge: use a stable FDB dst snapshot in RCU readers"}]}}}