In the Linux kernel, the following vulnerability has been resolved: bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap… (CVE-2026-53111)
A null pointer dereference vulnerability in the Linux kernel's bpf_lwt_xmit_push_encap helper was identified and resolved. The issue occurs because skb->_skb_refdst may not be initialized when skb is set up by the bpf_prog_test_run_skb function, leading to a kernel crash when bpf_lwt_push_ip_encap is executed. This vulnerability causes a denial of service via kernel crash but does not impact confidentiality or integrity.
AI Analysis
Technical Summary
The Linux kernel contained a null pointer dereference vulnerability in the bpf_lwt_xmit_push_encap helper function. This helper accesses skb_dst(skb)->dev to calculate required headroom, but when skb->_skb_refdst is uninitialized (as can happen when skb is set up by bpf_prog_test_run_skb), dereferencing this pointer leads to a kernel crash. The issue was reported with a kernel oops trace showing the null pointer dereference in bpf_lwt_push_ip_encap. The temporary fix involved initializing skb->_skb_refdst before bpf_test_run to prevent the null dereference.
Potential Impact
This vulnerability results in a denial of service condition by causing a kernel crash (null pointer dereference). There is no indication of confidentiality or integrity impact. The crash occurs when executing specific BPF program test runs that trigger the vulnerable code path.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The temporary mitigation involves initializing skb->_skb_refdst before running bpf_test_run to prevent the null pointer dereference. Users should monitor official Linux kernel advisories for an official fix and apply it once available.
In the Linux kernel, the following vulnerability has been resolved: bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap… (CVE-2026-53111)
Description
A null pointer dereference vulnerability in the Linux kernel's bpf_lwt_xmit_push_encap helper was identified and resolved. The issue occurs because skb->_skb_refdst may not be initialized when skb is set up by the bpf_prog_test_run_skb function, leading to a kernel crash when bpf_lwt_push_ip_encap is executed. This vulnerability causes a denial of service via kernel crash but does not impact confidentiality or integrity.
CVSS v3.1
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel contained a null pointer dereference vulnerability in the bpf_lwt_xmit_push_encap helper function. This helper accesses skb_dst(skb)->dev to calculate required headroom, but when skb->_skb_refdst is uninitialized (as can happen when skb is set up by bpf_prog_test_run_skb), dereferencing this pointer leads to a kernel crash. The issue was reported with a kernel oops trace showing the null pointer dereference in bpf_lwt_push_ip_encap. The temporary fix involved initializing skb->_skb_refdst before bpf_test_run to prevent the null dereference.
Potential Impact
This vulnerability results in a denial of service condition by causing a kernel crash (null pointer dereference). There is no indication of confidentiality or integrity impact. The crash occurs when executing specific BPF program test runs that trigger the vulnerable code path.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The temporary mitigation involves initializing skb->_skb_refdst before running bpf_test_run to prevent the null pointer dereference. Users should monitor official Linux kernel advisories for an official fix and apply it once available.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-gj9x-pqvx-p5mh
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-53111"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a629b119c2644c7f8d8656e
Added to database: 07/23/2026, 22:52:01 UTC
Last enriched: 07/23/2026, 22:54:47 UTC
Last updated: 07/27/2026, 08:52:02 UTC
Views: 6
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