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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99071: ipv4: do not warn on route notification size race

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 088ba80eef85fa7a5ad8f9e7c82b403c99242b56, 096ad0cb77f8da1928d04a0d170535e14ca6311b, 221ef5e1e44a044790f0f54e6aa237883f475a4d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 088ba80eef85fa7a5ad8f9e7c82b403c99242b56, 096ad0cb77f8da1928d04a0d170535e14ca6311b, 221ef5e1e44a044790f0f54e6aa237883f475a4d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Oct 23, 2026
Updated
Oct 30, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.12affected
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 8b35e7767fdee63e57948a1ec89d9238a651f8c6affected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 096ad0cb77f8da1928d04a0d170535e14ca6311baffected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 088ba80eef85fa7a5ad8f9e7c82b403c99242b56affected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 78a1cf5c54b2f795c81fedb530755a8d01cc84f0affected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 7dfa7ca97f3ac46353edd4cc44f7733758e4535baffected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before 221ef5e1e44a044790f0f54e6aa237883f475a4daffected · git
    • 680aea08e78c003292415518ad270bc20f9c80b1 and later · before e02a5b6588161673ef75a4bc5cdfb62bd493374daffected · git
    • before 5.12not affected · semver
    • 5.15.224 and later · up to and including 5.15.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.11-17.2.11-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-99069Oct 23, 2026 · Input: ati_remote2 - fix type confusion in device attribute handlers
    0Monitor
  • ← EarlierCVE-2026-99070Oct 23, 2026 · ipv6: do not warn on route notification size race
    0Monitor
  • Later →CVE-2026-99072Oct 23, 2026 · ipv4: stop route notification sizing when nexthop group shrinks
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux088ba80eef85fa7a5ad8f9e7c82b403c99242b56Vendor (CNA)
Linux Linux096ad0cb77f8da1928d04a0d170535e14ca6311bVendor (CNA)
Linux Linux221ef5e1e44a044790f0f54e6aa237883f475a4dVendor (CNA)
Linux Linux78a1cf5c54b2f795c81fedb530755a8d01cc84f0Vendor (CNA)
Linux Linux7dfa7ca97f3ac46353edd4cc44f7733758e4535bVendor (CNA)
Linux Linux8b35e7767fdee63e57948a1ec89d9238a651f8c6Vendor (CNA)
Linux Linuxe02a5b6588161673ef75a4bc5cdfb62bd493374dVendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.06.6.161.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 7, 2026+15 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records