CVE-2026-98317 neighbour: Enforce min/max to NDTPA_INTERVAL_PROBE_TIME_MS.
A local attacker with high privileges can cause a denial of service in the Linux kernel by exploiting an integer overflow in neighbor table probe time settings.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98317?
CVE-2026-98317 is a vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
neighbour: Enforce min/max to NDTPA_INTERVAL_PROBE_TIME_MS.
NDTPA_INTERVAL_PROBE_TIME_MS sets .type and .min but misses .validation_type, so no validation is applied:
# ynl --family rt-neigh --do setneightbl \ --json '{"name": "arp_cache", "parms": {"interval-probe-time-ms": 0}}'
# ynl --family rt-neigh --dump getneightbl --output-json | \ jq '.[] | select(.name == "arp_cache" and has("config")) | .parms["interval-probe-time-ms"]' 0
Moreover, nla_get_msecs() uses msecs_to_jiffies(), and u64 is silently cast to u32, so a larger value can bypass the min check:
e.g. 4294967296 == 0x100000000
# ynl --family rt-neigh --do setneightbl \ --json '{"name": "arp_cache", "parms": {"interval-probe-time-ms": 4294967296}}'
# ynl --family rt-neigh --dump getneightbl --output-json | \ jq '.[] | select(.name == "arp_cache" and has("config")) | .parms["interval-probe-time-ms"]' 0
msecs_to_jiffies() returns MAX_JIFFY_OFFSET if the value is larger than INT_MAX. Also, INT_MAX ms overflows int NEIGH_VAR() when HZ > 1000 (Alpha, MIPS), and passing a negative integer to queue_delayed_work(unsigned long delay) causes sign extension, which wraps around the expiry time to the past, resulting in it being handled as 0 delay in the timer wheel.
Let's use NLA_POLICY_FULL_RANGE() and limit the max to 1 day.
The same max check is applied to sysctl as well.
Note that this controls the probe interval for NTF_MANAGED entries, so the max of 1 day is unlikely to break any deployments.
Which versions are affected by CVE-2026-98317?
How do I fix CVE-2026-98317?
Apply the vendor's patch.
Is CVE-2026-98317 being exploited?
There is no known exploitation of CVE-2026-98317 in the wild and no public exploit code.
Sources
Also known as AZL-106332, BELL-CVE-2026-98317, DEBIAN-CVE-2026-98317, GHSA-52cr-c2c7-9x84, UBUNTU-CVE-2026-98317.