--- id: CVE-2026-68121 title: 'kernel: pppoe: reload header pointer after dev_hard_header() (CVE-2026-68121)' summary: >- A flaw was found in the Linux kernel's PPPoE (Point-to-Point Protocol over Ethernet) implementation. This vulnerability occurs because a pointer to network packet data is not updated after memory is reallocated, leading to the use of an ou… severity: high cvss: 7.3 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H' cvssSource: vendor cwe: CWE-825 vendor: Red Hat product: Red Hat Enterprise Linux BaseOS E4S (v.9.4) affected: - enterprise_linux 9 - openshift_container_platform 4 - nvidia_for_rhel 10 - enterprise_linux_server_extension_v_6_els_extension - enterprise_linux_server_optional_extension_v_6_els_extension - enterprise_linux_server_v_7_els - enterprise_linux_for_real_time_v_7_els - enterprise_linux_server_optional_v_7_els - openshift_container_platform 4.19 - openshift_container_platform 4.20 - openshift_container_platform 4.21 - openshift_container_platform 4.22 - enterprise_linux_appstream_eus_v_10_0 - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_e4s_v_9_2 - enterprise_linux_appstream_e4s_v_9_4 - enterprise_linux_appstream_eus_v_9_6 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_eus_v_10_0 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_aus_v_8_4 - enterprise_linux_baseos_eus_extension_v_8_4 - enterprise_linux_baseos_aus_v_8_6 - enterprise_linux_baseos_eus_extension_v_8_6 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_e4s_v_9_2 - enterprise_linux_baseos_e4s_v_9_4 - enterprise_linux_baseos_eus_v_9_6 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_eus_v_10_0 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - codeready_linux_builder_eus_v_9_6 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_eus_v_10_0 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_e4s_v_9_2 patched: - nvidia_for_rhel 10 - enterprise_linux_server_extension_v_6_els_extension - enterprise_linux_server_optional_extension_v_6_els_extension - enterprise_linux_server_v_7_els - enterprise_linux_for_real_time_v_7_els - enterprise_linux_server_optional_v_7_els - openshift_container_platform 4.19 - openshift_container_platform 4.20 - openshift_container_platform 4.21 - openshift_container_platform 4.22 - enterprise_linux_appstream_eus_v_10_0 - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_e4s_v_9_2 - enterprise_linux_appstream_e4s_v_9_4 - enterprise_linux_appstream_eus_v_9_6 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_eus_v_10_0 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_aus_v_8_4 - enterprise_linux_baseos_eus_extension_v_8_4 - enterprise_linux_baseos_aus_v_8_6 - enterprise_linux_baseos_eus_extension_v_8_6 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_e4s_v_9_2 - enterprise_linux_baseos_e4s_v_9_4 - enterprise_linux_baseos_eus_v_9_6 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_eus_v_10_0 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - codeready_linux_builder_eus_v_9_6 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_eus_v_10_0 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_e4s_v_9_2 - enterprise_linux_real_time_for_nfv_e4s_v_9_4 - enterprise_linux_real_time_for_nfv_eus_v_9_6 published: '2026-08-10' updated: '2026-10-21' sourceUpdated: '2026-10-21T09:20:41+00:00' source: CSAF sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68121.json' references: - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68121.json - url: 'https://access.redhat.com/security/cve/CVE-2026-68121' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2513233' - url: 'https://access.redhat.com/security/vulnerabilities/RHSB-2026-011' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-68121' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-68121' - url: >- https://lore.kernel.org/linux-cve-announce/2026081056-CVE-2026-68121-b20f@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:73788' - url: 'https://access.redhat.com/errata/RHSA-2026:71649' - url: 'https://access.redhat.com/errata/RHSA-2026:71687' - url: 'https://access.redhat.com/errata/RHSA-2026:71657' - url: 'https://access.redhat.com/errata/RHSA-2026:83479' - url: 'https://access.redhat.com/errata/RHSA-2026:74377' - url: 'https://access.redhat.com/errata/RHSA-2026:74379' - url: 'https://access.redhat.com/errata/RHSA-2026:83540' - url: 'https://access.redhat.com/errata/RHSA-2026:71599' - url: 'https://access.redhat.com/errata/RHSA-2026:71602' - url: 'https://access.redhat.com/errata/RHSA-2026:71601' - url: 'https://access.redhat.com/errata/RHSA-2026:71569' - url: 'https://access.redhat.com/errata/RHSA-2026:71631' - url: 'https://access.redhat.com/errata/RHSA-2026:71700' - url: 'https://access.redhat.com/errata/RHSA-2026:71329' - url: 'https://access.redhat.com/errata/RHSA-2026:71565' - url: 'https://access.redhat.com/errata/RHSA-2026:71592' - url: 'https://access.redhat.com/errata/RHSA-2026:71594' - url: 'https://access.redhat.com/errata/RHSA-2026:71330' - url: 'https://access.redhat.com/errata/RHSA-2026:71606' - url: 'https://git.kernel.org/stable/c/7a56e7c9b08e08fd55a1bcada24cf4fe3782b722' - url: 'https://git.kernel.org/stable/c/6eed5ae7887a93160803d2b81ff88e75eefd4a4c' - url: 'https://git.kernel.org/stable/c/ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a' - url: 'https://git.kernel.org/stable/c/e6493a4d1ee17595766165fa446d45b7e0c318d0' - url: 'https://git.kernel.org/stable/c/7e9fbd7f96bcde63a7c798fe16b38cedee7a1501' - url: 'https://git.kernel.org/stable/c/6866abf59976d273164a6624234d96a967280223' - url: 'https://git.kernel.org/stable/c/bed4caecd723693f750e13adbb2c42ca1249a3fd' - url: 'https://git.kernel.org/stable/c/e9c238f6fe42fb1b4dba3a578277de32cb487937' tags: - csaf - vex - red-hat - exploit-available - cve.org epss: 0.00367 epssPercentile: 0.30429 exploits: github: 3 githubRepos: - 'https://github.com/suominen/pppoeject' - 'https://github.com/0xBlackash/CVE-2026-68121' - 'https://github.com/HORKimhab/CVE-2026-68121' checkedAt: '2026-10-27T19:08:28.056Z' exploitAvailable: true ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-16T15:44:11.187043Z' scores: vendor: 7.3 cna: 7.8 ingestedAt: '2026-10-16T17:24:46.840Z' --- ## Overview A flaw was found in the Linux kernel's PPPoE (Point-to-Point Protocol over Ethernet) implementation. This vulnerability occurs because a pointer to network packet data is not updated after memory is reallocated, leading to the use of an outdated memory address. An attacker with local access could potentially trigger this condition, causing memory corruption. This could result in a system crash (denial of service) or other unpredictable system behavior. ## Vendor advisories - **RHSA-2026:73788** · Red Hat · fixed in: NVIDIA for RHEL 10 · released 2026-09-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:73788) - **RHSA-2026:71649** · Red Hat · fixed in: Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION), Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71649) - **RHSA-2026:71687** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71687) - **RHSA-2026:71657** · Red Hat · fixed in: Red Hat Enterprise Linux for Real Time (v. 7 ELS) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71657) - **RHSA-2026:83479** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.19 · released 2026-10-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:83479) - **RHSA-2026:74377** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.20 · released 2026-10-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:74377) - **RHSA-2026:74379** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.21 · released 2026-10-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:74379) - **RHSA-2026:83540** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-10-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:83540) - **RHSA-2026:71599** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71599) - **RHSA-2026:71602** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71602) - **RHSA-2026:71601** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71601) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68121.json) **kernel: pppoe: reload header pointer after dev_hard_header()** — rated Important by Red Hat. Released 2026-08-10, updated 2026-10-21. Affected: - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 Fixed: - NVIDIA for RHEL 10 - Red Hat Enterprise Linux Server -EXTENSION(v. 6 ELS-EXTENSION) - Red Hat Enterprise Linux Server Optional -EXTENSION (v. 6 ELS -EXTENSION) - Red Hat Enterprise Linux Server (v. 7 ELS) - Red Hat Enterprise Linux for Real Time (v. 7 ELS) - Red Hat Enterprise Linux Server Optional (v. 7 ELS) - Red Hat OpenShift Container Platform 4.19 - Red Hat OpenShift Container Platform 4.20 - Red Hat OpenShift Container Platform 4.21 - Red Hat OpenShift Container Platform 4.22 - Red Hat Enterprise Linux AppStream EUS (v. 10.0) - Red Hat Enterprise Linux AppStream (v. 10) - Red Hat Enterprise Linux AppStream E4S (v.9.2) - Red Hat Enterprise Linux AppStream E4S (v.9.4) - Red Hat Enterprise Linux AppStream EUS (v.9.6) - Red Hat Enterprise Linux AppStream (v. 9) - Red Hat Enterprise Linux BaseOS EUS (v. 10.0) - Red Hat Enterprise Linux BaseOS (v. 10) - Red Hat Enterprise Linux BaseOS (v. 8) - Red Hat Enterprise Linux BaseOS AUS (v.8.4) - Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) - Red Hat Enterprise Linux BaseOS AUS (v.8.6) - Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) - Red Hat Enterprise Linux BaseOS E4S (v.8.8) - Red Hat Enterprise Linux BaseOS TUS (v.8.8) - Red Hat Enterprise Linux BaseOS E4S (v.9.2) - Red Hat Enterprise Linux BaseOS E4S (v.9.4) - Red Hat Enterprise Linux BaseOS EUS (v.9.6) - Red Hat Enterprise Linux BaseOS (v. 9) - Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) - Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) - Red Hat Enterprise Linux CRB (v. 8) - Red Hat CodeReady Linux Builder EUS (v.9.6) - Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) - Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) - Red Hat Enterprise Linux Real Time for NFV (v. 10) - Red Hat Enterprise Linux NFV (v. 8) - Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) - Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) - Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) No fix planned: - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 ## Remediation Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:73788 For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:71649 For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:71687 Workarounds / mitigations: - See the security bulletin for a detailed mitigation procedure.