# CVE-2026-99071: ipv4: do not warn on route notification size race CVE-2026-99071 is fixed in 19 products on 1 platform, first by DEBIAN-CVE-2026-99071, released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-99071 - Priority: Routine - CVSS: 1.9 (Low) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Oct 23, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99071 ## Description In the Linux kernel, the following vulnerability has been resolved: ipv4: do not warn on route notification size race Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed") added asynchronous route notifications for hardware flag changes. fib_alias_hw_flags_set() sizes the skb with fib_nlmsg_size() and later fills it with fib_dump_info() while holding only RCU. With nexthop compatibility mode enabled, a concurrent replacement can grow the group between these independent snapshots. fib_dump_info() can then legitimately return -EMSGSIZE, so the warning does not prove a sizing bug. Remove the warning. The existing error path still frees the skb and reports the error to listeners. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel-livepatch-6.12.113-138.209 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-devel amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-headers amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-99071](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99071.md) | Oct 24, 2026 | | Linux | linux Debian 14 | 7.2.11-1 | [DEBIAN-CVE-2026-99071](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99071.md) | Oct 24, 2026 | | Linux | perf6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | python3-perf6.12 amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | | Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.113-138.209.amzn2023 | [ALAS2023-2026-3335](https://patchblox.com/security/data/fix/linux/alas2023-2026-3335.md) | Nov 7, 2026 | --- Data as of 2026-11-09T07:25:28Z UTC. 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