CVE-2026-68121: Linux kernel · pppoe: reload header pointer after dev_hard_header()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in e6493a4d1ee17595766165fa446d45b7e0c318d0 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:07 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 30% 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 e6493a4d1ee17595766165fa446d45b7e0c318d0, e9c238f6fe42fb1b4dba3a578277de32cb487937, bed4caecd723693f750e13adbb2c42ca1249a3fd +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 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: pppoe: reload header pointer after dev_hard_header() pppoe_sendmsg() saves a pointer to the PPPoE header before calling dev_hard_header(). Device header callbacks are allowed to reallocate the skb head, invalidating pointers into it. This can happen when a send is blocked in copy_from_user() while the first non-Ethernet port is added to an empty team device. The team's delegated GRE header callback then expands the skb head. PPPoE subsequently writes six bytes through the stale pointer into the freed head. Reload the PPPoE header through the skb's network-header offset after device header creation. pskb_expand_head() updates that offset when it relocates the head.
References
- git.kernel.org/stable/c/7a56e7c9b08e08fd55a1bcada24cf4fe3782b722 (opens in a new tab)
- git.kernel.org/stable/c/6eed5ae7887a93160803d2b81ff88e75eefd4a4c (opens in a new tab)
- git.kernel.org/stable/c/ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a (opens in a new tab)
- git.kernel.org/stable/c/e6493a4d1ee17595766165fa446d45b7e0c318d0 (opens in a new tab)
- git.kernel.org/stable/c/7e9fbd7f96bcde63a7c798fe16b38cedee7a1501 (opens in a new tab)
- git.kernel.org/stable/c/6866abf59976d273164a6624234d96a967280223 (opens in a new tab)
- git.kernel.org/stable/c/bed4caecd723693f750e13adbb2c42ca1249a3fd (opens in a new tab)
- git.kernel.org/stable/c/e9c238f6fe42fb1b4dba3a578277de32cb487937 (opens in a new tab)