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CVE-2026-68121

HIGHCVSS 7.8/10EPSS 0.14%

Last modified

CVE-2026-68121 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.14% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.14%

3.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6eed5ae7887a93160803d2b81ff88e75eefd4a4c; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e6493a4d1ee17595766165fa446d45b7e0c318d0; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6866abf59976d273164a6624234d96a967280223; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < bed4caecd723693f750e13adbb2c42ca1249a3fd; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e9c238f6fe42fb1b4dba3a578277de32cb487937
LinuxLinux2.6.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-68121?
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.
How severe is CVE-2026-68121?
CVE-2026-68121 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.
How do I fix CVE-2026-68121?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST