Kernel-level privilege escalation affecting Linux network namespaces and containerized/multi-tenant hosts; widely deployed OS across enterprises.
CVE-2026-63829
Linux kernel GRE/ERSPAN changelink allows cross-netns privilege/traffic tampering
Is CVE-2026-63829 being exploited?
Not confirmed. CVE-2026-63829 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.13% probability of exploitation in the next 30 days.
How severe is CVE-2026-63829?
CVE-2026-63829 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63829?
Yes. A fix has been recorded for CVE-2026-63829. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63829 affect?
CVE-2026-63829 affects Linux kernel (net: ip_gre, erspan), Containers and hosts using network namespaces, Virtualization and multi-tenant Linux systems. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63829?
Apply kernel updates with the changelink CAP_NET_ADMIN fix and restrict CAP_NET_ADMIN in namespaces.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local privilege escalation across network namespaces: attacker with CAP_NET_ADMIN in one netns can modify GRE/ERSPAN tunnels in another, enabling traffic interception or lateral compromise.
Patch when possible
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 19275943d8fe903eb7b9aa53e380e41efd042ada
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 866b0f5ae599490bd496fd84581c68ac8b94e6af
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 92b766fc55156e0da2ecd0c2302c971118f8a229
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < e54c05ed3d9c28733fb9e5837219aca3691defa3
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 9831bc9ecb402957810c2045c663fbfe9b09e296
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 1697957eb0971d420dde42862b88eb43506a1105
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 47b5d3d506609b08b2e1f7c14f0b681a1953d572
- affected>= b57708add31494175be741ed3fd24023b50c3423 and < 8165f7ff57d9667d2bb477ef6af83ede7fed4ad7
- affected3.16
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.