CVE-2026-63829: Linux kernel · Missing Authorization
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in e54c05ed3d9c28733fb9e5837219aca3691defa3 : patch Linux kernel soon.
Data as of 26 Oct 2026, 16:39 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in e54c05ed3d9c28733fb9e5837219aca3691defa3, 19275943d8fe903eb7b9aa53e380e41efd042ada, 1697957eb0971d420dde42862b88eb43506a1105 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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.
References
- git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada (opens in a new tab)
- git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af (opens in a new tab)
- git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229 (opens in a new tab)
- git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3 (opens in a new tab)
- git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296 (opens in a new tab)
- git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105 (opens in a new tab)
- git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572 (opens in a new tab)
- git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7 (opens in a new tab)