CVE-2026-72052

Cross-namespace tunnel modification via incomplete capability check

Published Aug 15, 2026 · Updated Aug 15, 2026

Authorization bypass in the Linux kernel allows local users to rewrite IPv6 GRE and ERSPAN tunnels across network namespaces. The ip6gre_changelink() and ip6erspan_changelink() paths validate CAP_NET_ADMIN only in dev_net(dev), not the tunnel link namespace t->net. A caller needs CAP_NET_ADMIN in the device namespace but can then modify a tunnel in another namespace without equivalent authority there.

CVSS severity6.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authorization bypass in the Linux kernel allows local users to rewrite IPv6 GRE and ERSPAN tunnels across network namespaces. The ip6gre_changelink() and ip6erspan_changelink() paths validate CAP_NET_ADMIN only in dev_net(dev), not the tunnel link namespace t->net. A caller needs CAP_NET_ADMIN in the device namespace but can then modify a tunnel in another namespace without equivalent authority there.

The record

CVE
CVE-2026-72052
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.19.100 <4.20
  2. Affected versionversion=5.4.16 <5.5
  3. Affected versionversion=5.5
  4. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <03d8843b143ebbbfaf48511922abc6e886575a61
  5. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <0caa9f348f8b5356900de77b0bb89a697c4aff20
  6. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <129f8939e5af683cec3a1a5edcb40a64636ad81e
  7. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <1d4d8ee002083ca4ead5353662bf8362428af57f
  8. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <220162c9fedbe992da70d70f50a10da4f45f914c
  9. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <c38c8b0db3c65b597e7ece317b6cb59de3d15e69
  10. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <e3724dedf57761c6de52f4d604ec74f66fd61611
  11. Affected versionversion=690afc165bb314354667f67157c1a1aea7dc797a <f00a50876d2818bd6dc86fa98b3ef360884c53c8
  12. Affected versionversion=7943bb0f06365cf5e32f3cf8a6b29eeae981fb8a
  13. Affected versionversion=d0201d2405dac8d9b16773e97709925e397552d0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.19.100 <4.20; version=5.4.16 <5.5; version=5.5; version=690afc165bb314354667f67157c1a1aea7dc797a <03d8843b143ebbbfaf48511922abc6e886575a61; version=690afc165bb314354667f67157c1a1aea7dc797a <0caa9f348f8b5356900de77b0bb89a697c4aff20; version=690afc165bb314354667f67157c1a1aea7dc797a <129f8939e5af683cec3a1a5edcb40a64636ad81e; version=690afc165bb314354667f67157c1a1aea7dc797a <1d4d8ee002083ca4ead5353662bf8362428af57f; version=690afc165bb314354667f67157c1a1aea7dc797a <220162c9fedbe992da70d70f50a10da4f45f914c; version=690afc165bb314354667f67157c1a1aea7dc797a <c38c8b0db3c65b597e7ece317b6cb59de3d15e69; version=690afc165bb314354667f67157c1a1aea7dc797a <e3724dedf57761c6de52f4d604ec74f66fd61611; version=690afc165bb314354667f67157c1a1aea7dc797a <f00a50876d2818bd6dc86fa98b3ef360884c53c8; version=7943bb0f06365cf5e32f3cf8a6b29eeae981fb8a; version=d0201d2405dac8d9b16773e97709925e397552d0

Published CVSS scores

6.5Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
8.8OSVCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo