CVE-2026-99121ipv4: avoid divide by zero in fib_rebalance
- —Not scoredno CVSS score yet
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: avoid divide by zero in fib_rebalance fib_rebalance() computes the total eligible nexthop weight in one pass and programs upper bounds in a second pass. A concurrent change to ignore_routes_with_linkdown can make the first pass return zero while the second pass sees an eligible nexthop, resulting in division by zero. If the first pass reports a zero total, set each nexthop upper bound to -1 and skip the division. This matches the IPv6 fix in commit d2c26c2911dd ("ipv6: avoid divide by zero in rt6_multipath_rebalance") and preserves the lock-free rebalance path.
Timeline
ID reserved
By Linux
- 33 days later
· 33 days later
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < baf3a767b2845eb8e68f056ee4aa5b41b151e990
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < f655a26490e705ec76a79db7f412847fda342b39
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < 7c68f4de5090b17b63b9a0a3b01b3807e01a296a
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < 226a974054acbd892560bfa67f0ae8ffe271a736
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < 0800c92ca5d1983df6843a5435299978901d1d02
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < 5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < d5520e815c4b1427104ce1428ee23821f2aa824d
- affected 0e884c78ee19e902f300ed147083c28a0c6302f0 – < 5046d2880fec7d49ebed2fd2866747ee1d06ad71
- affected 4.4
- unaffected < 4.4
- unaffected 5.10.273 – ≤ 5.10.*
- unaffected 5.15.224 – ≤ 5.15.*
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.161 – ≤ 6.6.*
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/baf3a767b2845eb8e68f056ee4aa5b41b151e990 (opens in a new tab)
- https://git.kernel.org/stable/c/f655a26490e705ec76a79db7f412847fda342b39 (opens in a new tab)
- https://git.kernel.org/stable/c/7c68f4de5090b17b63b9a0a3b01b3807e01a296a (opens in a new tab)
- https://git.kernel.org/stable/c/226a974054acbd892560bfa67f0ae8ffe271a736 (opens in a new tab)
- https://git.kernel.org/stable/c/0800c92ca5d1983df6843a5435299978901d1d02 (opens in a new tab)
- https://git.kernel.org/stable/c/5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f (opens in a new tab)
- https://git.kernel.org/stable/c/d5520e815c4b1427104ce1428ee23821f2aa824d (opens in a new tab)
- https://git.kernel.org/stable/c/5046d2880fec7d49ebed2fd2866747ee1d06ad71 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-112021 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-99121)Record last updated .