--- id: CVE-2026-63924 title: >- kernel: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo() (CVE-2026-63924) summary: >- A flaw was found in the Linux kernel's handling of IPv6 extended headers. Specifically, the `ipv6_hop_jumbo()` function, which processes jumbo payloads, can modify internal packet buffer (skb) pointers. However, the network header (nh) poi… severity: high cvss: 7 cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: vendor cwe: CWE-825 vendor: Red Hat product: Red Hat Enterprise Linux BaseOS E4S (v.9.4) affected: - enterprise_linux 10 - enterprise_linux 7 - enterprise_linux 8 - enterprise_linux 9 - enterprise_linux_server_extension_v_6_els_extension - enterprise_linux_server_optional_extension_v_6_els_extension - enterprise_linux_appstream_eus_v_10_0 - 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_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 - 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_e4s_v_9_4 - enterprise_linux_real_time_for_nfv_eus_v_9_6 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_eus_v_10_0 - enterprise_linux_real_time_e4s_v_9_4 - enterprise_linux_real_time_eus_v_9_6 - enterprise_linux_real_time_v_9 patched: - enterprise_linux_server_extension_v_6_els_extension - enterprise_linux_server_optional_extension_v_6_els_extension - enterprise_linux_appstream_eus_v_10_0 - 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_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 - 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_e4s_v_9_4 - enterprise_linux_real_time_for_nfv_eus_v_9_6 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_eus_v_10_0 - enterprise_linux_real_time_e4s_v_9_4 - enterprise_linux_real_time_eus_v_9_6 - enterprise_linux_real_time_v_9 published: '2026-07-19' updated: '2026-10-16' sourceUpdated: '2026-10-16T17:13:02+00:00' source: CSAF sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63924.json' references: - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63924.json - url: 'https://access.redhat.com/security/cve/CVE-2026-63924' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2502326' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-63924' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63924' - url: >- https://lore.kernel.org/linux-cve-announce/2026071948-CVE-2026-63924-ec60@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:83796' - url: 'https://access.redhat.com/errata/RHSA-2026:83707' - url: 'https://access.redhat.com/errata/RHSA-2026:77218' - url: 'https://access.redhat.com/errata/RHSA-2026:77219' - url: 'https://access.redhat.com/errata/RHSA-2026:76739' - url: 'https://git.kernel.org/stable/c/b3ac54e5c905f86d22b502eacb5686a282c5659f' - url: 'https://git.kernel.org/stable/c/645b99b1a185c91a79bdac4c5de0f91b212d64f0' - url: 'https://git.kernel.org/stable/c/9e883eaa878f4337b5873c706efb5a192364ed18' - url: 'https://git.kernel.org/stable/c/bddaa4dfc7f36e1ee343a0622f69288af2b9ace9' - url: 'https://git.kernel.org/stable/c/72af7beae774e46ed543f3f2f267bf0a141bfcdd' - url: 'https://git.kernel.org/stable/c/c512e1c819dfbf6ae95ee7a44b65b9ad98979157' - url: 'https://git.kernel.org/stable/c/2b56bbd928c030894c270cd33d60286326919458' - url: 'https://git.kernel.org/stable/c/d47548a36639095939f4747d4c43f2271366f565' tags: - csaf - vex - red-hat - cve.org - score-dispute epss: 0.00714 epssPercentile: 0.52757 ssvc: exploitation: none automatable: 'yes' technicalImpact: total timestamp: '2026-10-16T15:33:33.023391Z' scores: vendor: 7 cna: 9.8 ingestedAt: '2026-10-16T17:24:46.778Z' --- ## Overview A flaw was found in the Linux kernel's handling of IPv6 extended headers. Specifically, the `ipv6_hop_jumbo()` function, which processes jumbo payloads, can modify internal packet buffer (skb) pointers. However, the network header (nh) pointer is not recomputed after these modifications. This oversight could lead to incorrect data processing, potentially causing system instability or a denial of service (DoS) due to malformed packets. ## Vendor advisories - **RHSA-2026:83796** · 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 2026-10-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:83796) - **RHSA-2026:83707** · 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 2026-10-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:83707) - **RHSA-2026:77218** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-10-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:77218) - **RHSA-2026:77219** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:77219) - **RHSA-2026:76739** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:76739) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63924.json) **kernel: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()** — rated Important by Red Hat. Released 2026-07-19, updated 2026-10-16. Affected: - Red Hat Enterprise Linux 10 - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 Fixed: - 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 AppStream EUS (v. 10.0) - 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 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 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 E4S (v.9.4) - Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) - Red Hat Enterprise Linux Real Time for NFV (v. 9) - Red Hat Enterprise Linux Real Time EUS (v. 10.0) - Red Hat Enterprise Linux Real Time E4S (v.9.4) - Red Hat Enterprise Linux Real Time EUS (v.9.6) - Red Hat Enterprise Linux Real Time (v. 9) No fix planned: - Red Hat Enterprise Linux 10 - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 ## Remediation 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-2026:83796 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-2026:83707 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-2026:77218 Workarounds / mitigations: - Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.