VulnerabilityPublished 23 Oct 2026

CVE-2026-99073: Linux kernel · ipv4: stop exception dump when nexthop group shrinks

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f91e472821e32f58b03eb631e20a67157e2b928b : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:07 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f91e472821e32f58b03eb631e20a67157e2b928b, b9a30bb7b831e8c5a47fadbdf1760918aaf009cc, 21cba134c30c17ae55f468b5809336437df5d7e6 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to f91e472821e32f58b03eb631e20a67157e2b928b, b9a30bb7b831e8c5a47fadbdf1760918aaf009cc, 21cba134c30c17ae55f468b5809336437df5d7e6 or 4f4afc07dcb2edd4f9afa36595373f8cdb9b58c2.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 4ce5dc9316de50e0da84beafe55d1344f829cece, < f91e472821e32f58b03eb631e20a67157e2b928b	Fixed in f91e472821e32f58b03eb631e20a67157e2b928b
LinuxLinux	Affected ≥ 4ce5dc9316de50e0da84beafe55d1344f829cece, < b9a30bb7b831e8c5a47fadbdf1760918aaf009cc	Fixed in b9a30bb7b831e8c5a47fadbdf1760918aaf009cc
LinuxLinux	Affected ≥ 4ce5dc9316de50e0da84beafe55d1344f829cece, < 21cba134c30c17ae55f468b5809336437df5d7e6	Fixed in 21cba134c30c17ae55f468b5809336437df5d7e6
LinuxLinux	Affected ≥ 4ce5dc9316de50e0da84beafe55d1344f829cece, < 4f4afc07dcb2edd4f9afa36595373f8cdb9b58c2	Fixed in 4f4afc07dcb2edd4f9afa36595373f8cdb9b58c2
LinuxLinux	Affected =6.9	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: stop exception dump when nexthop group shrinks Commit 4ce5dc9316de ("inet: switch inet_dump_fib() to RCU protection") allowed IPv4 FIB dumps to run concurrently with nexthop replacement. fib_dump_info_fnhe() uses fib_info_num_path() as the loop bound, then fib_info_nhc() independently reloads nh->nh_grp. If RTM_NEWNEXTHOP replaces a group with fewer paths between those loads, fib_info_nhc() returns NULL and the dump dereferences it through nhc_flags. Stop the walk when the indexed path is absent. Nexthop groups are dense, so the current snapshot has no later path.

References

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