net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink
Priority LOW 39CWE-862Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 16 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-862.
Summary
In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->net. They differ once the device is created in or moved to a netns other than the one the request runs in. The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a caller privileged there but not in t->net can rewrite a tunnel that lives in t->net. Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is skipped when the link netns is dev_net(dev), where the rtnl path already checked it. The other patches in this series use the same helper. Gate ipgre_changelink() and erspan_changelink() with it, at the top of the op before any attribute is parsed, because the parsers update live tunnel fields first. ipgre_netlink_parms() sets t->collect_md before ip_tunnel_changelink() runs. Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().") added the same check on the ioctl path. This adds it on RTM_NEWLINK.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00148 3rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.261, 5.15.212, 6.1.178 +5Red Hat: 4 advisoriesRed Hat: 16 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.16 and later | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 3.16 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 3.16 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.16 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2
Red Hat 4 advisories
- RHSA-2026:76739 Released 2026-10-08 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.55.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.55.1.el9_8, kernel-64k-devel-5.14.0-687.55.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.55.1.el9_8, kernel-64k-5.14.0-687.55.1.el9_8, kernel-64k-core-5.14.0-687.55.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.55.1.el9_8, libperf-5.14.0-687.55.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-64k-5.14.0-687.55.1.el9_8, kernel-rt-64k-core-5.14.0-687.55.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-core-5.14.0-687.55.1.el9_8, kernel-rt-debug-5.14.0-687.55.1.el9_8 +9
- RHSA-2026:76738 Released 2026-10-08 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- 10Base-SMTV kernel-modules-internal-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.63.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.63.1.el10_2, kernel-64k-devel-6.12.0-211.63.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.63.1.el10_2, kernel-64k-6.12.0-211.63.1.el10_2, kernel-64k-core-6.12.0-211.63.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.63.1.el10_2, libperf-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.63.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-64k-6.12.0-211.63.1.el10_2, kernel-rt-64k-core-6.12.0-211.63.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-core-6.12.0-211.63.1.el10_2, kernel-rt-debug-6.12.0-211.63.1.el10_2 +9
- RHSA-2026:75747 Released 2026-10-05 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.171.1.el8_10, kernel-4.18.0-553.171.1.el8_10, kernel-abi-stablelists-4.18.0-553.171.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.171.1.el8_10
Show 1 more Red Hat advisories
- RHSA-2026:75746 Released 2026-10-05 · Red Hat rating Importantkernel-rt security, bug fix, and enhancement update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-4.18.0-553.171.1.rt7.512.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-4.18.0-553.171.1.rt7.512.el8_10 +7
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| 10Base-SMTV | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:76739 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:75747 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:76739 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:75747 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:76739 |
| Red Hat Enterprise Linux Hidden (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:75746 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:75746 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:76739 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:76738 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:76739 |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-63829
- 2026-10-03 Alias added: GHSA-6wc5-2mjj-pmr6
- 2026-10-05 Fix available: RHSA-2026:75746 · Red Hat
- 2026-10-05 Fix available: RHSA-2026:75747 · Red Hat
- 2026-10-05 Fix available: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8), Red Hat Enterprise Linux NFV (v. 8) +1 · Red Hat
- 2026-10-09 Fix available: RHSA-2026:76739 · Red Hat
- 2026-10-09 Fix available: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) +2 · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-26 Fix available: RHSA-2026:76738 · Red Hat
- 2026-10-26 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 8
- https://git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada
- https://git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af
- https://git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229
- https://git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3
- https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296
- https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105
- https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572
- https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7
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- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-63829 · CVE Program
- CVE-2026-63829 · NVD
- FIRST EPSS
- GHSA-6wc5-2mjj-pmr6 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-63829 · Red Hat security data · CC BY 4.0
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