Kernel crash via unchecked BPF NAT type
Published Oct 18, 2026 · Updated Oct 18, 2026
Invalid NAT handling in Linux netfilter allows local users to crash the kernel through crafted calls to bpf_ct_set_nat_info(). The helper passes unchecked manipulation types to nf_nat_setup_info(), which warns but continues, leaving conntrack cleanup to unlink an uninitialized list node. Exposure requires an XDP or TC-BPF program invoking the helper; enabling panic_on_warn instead causes a kernel panic at the warning.
Summary
What happened
Invalid NAT handling in Linux netfilter allows local users to crash the kernel through crafted calls to bpf_ct_set_nat_info(). The helper passes unchecked manipulation types to nf_nat_setup_info(), which warns but continues, leaving conntrack cleanup to unlink an uninitialized list node. Exposure requires an XDP or TC-BPF program invoking the helper; enabling panic_on_warn instead causes a kernel panic at the warning.
The record
- CVE
- CVE-2026-98793
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0fabd2aa199faeb8754aee94658f2c48ccb2c8c3 <16d464013ec2267b00a83f4bfbb97b3ecc63bfa7
- Affected versionversion=0fabd2aa199faeb8754aee94658f2c48ccb2c8c3 <58108f05b0502448f6bb612ee2eccc63bd6449cb
- Affected versionversion=0fabd2aa199faeb8754aee94658f2c48ccb2c8c3 <ea777dc90ab37e64fa4b92f6fcf3b5edcef5e058
- Affected versionversion=0fabd2aa199faeb8754aee94658f2c48ccb2c8c3 <f6143ae109df56d51d5536e813deb19eee7a6205
- Affected versionversion=6.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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