# ipv4: avoid divide by zero in fib_rebalance

CVE record · `CVE-2026-99121`

- **Identifiers:** `CVE-2026-99121`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 28 Oct 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 28 Oct 2026, 10:34 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before baf3a767b2845eb8e68f056ee4aa5b41b151e990` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before f655a26490e705ec76a79db7f412847fda342b39` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before 7c68f4de5090b17b63b9a0a3b01b3807e01a296a` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before 226a974054acbd892560bfa67f0ae8ffe271a736` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before 0800c92ca5d1983df6843a5435299978901d1d02` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before 5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before d5520e815c4b1427104ce1428ee23821f2aa824d` (git)
  - affected: `0e884c78ee19e902f300ed147083c28a0c6302f0 to before 5046d2880fec7d49ebed2fd2866747ee1d06ad71` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.4`
  - unaffected: `before 4.4` (semver)
  - unaffected: `5.10.273 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.224 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.161 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.115 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.59 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.13 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0019, the 8th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 28 Oct 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-99121](https://www.cve.org/CVERecord?id=CVE-2026-99121)
- [NVD: CVE-2026-99121](https://nvd.nist.gov/vuln/detail/CVE-2026-99121)

### References from the CNA

- <https://git.kernel.org/stable/c/baf3a767b2845eb8e68f056ee4aa5b41b151e990>
- <https://git.kernel.org/stable/c/f655a26490e705ec76a79db7f412847fda342b39>
- <https://git.kernel.org/stable/c/7c68f4de5090b17b63b9a0a3b01b3807e01a296a>
- <https://git.kernel.org/stable/c/226a974054acbd892560bfa67f0ae8ffe271a736>
- <https://git.kernel.org/stable/c/0800c92ca5d1983df6843a5435299978901d1d02>
- <https://git.kernel.org/stable/c/5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f>
- <https://git.kernel.org/stable/c/d5520e815c4b1427104ce1428ee23821f2aa824d>
- <https://git.kernel.org/stable/c/5046d2880fec7d49ebed2fd2866747ee1d06ad71>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-99121>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-99121/>. Everything for agents: <https://agentprime.io/llms.txt>.