CVE-2026-98377
N/AIn the Linux kernel, the following vulnerability has been resolved: vlan: require the MAC header to be present in __vlan_insert_inner_tag() __vlan_insert_inner_tag() only guarantees head room via skb_cow_head(), never that mac_len bytes of MAC header are present. Its ETH_HLEN wrappers - __vlan_insert_tag() under skb_vlan_push(), and vlan_insert_tag() under validate_xmit_vlan() on the generic transmit path - therefore rewrite the first 16 bytes at skb->data: a 12-byte memmove plus two 2-byte stores at +12 and +14. No caller supplies the bound, while the pop helpers use skb_ensure_writable()/pskb_may_pull(). An IFF_TUN device has hard_header_len == 0, so packet_snd() accepts a one-byte AF_PACKET/SOCK_RAW frame. The first vlan push only sets a hwaccel tag; the next - clsact "action vlan push" or bpf_skb_vlan_push() - enters the helper with skb->len still 1. The head comes from skbuff_small_head without __GFP_ZERO, so each push drags bytes from beyond skb->tail into the frame. After three the one-byte send leaves as 13 bytes carrying 11 bytes of uninitialised slab: 0000: 5a b3 62 12 80 88 ff ff 00 b3 62 12 81 `------------------------------' only 0x5a was sent; the rest is slab, here the top 56 bits of a linear-map address Require the MAC header the helper rewrites to be present, so such a frame is dropped rather than transmitted.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 5th percentile
Impact if exploited
—CVSS · not scored
- No impact metrics
Proof of concept
No public PoC is currently catalogued.
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References and research data (JSON)
Vendor product assessments
Showing 32 of 278 vendor product statements; 246 omitted. Read the full vendor advisory.
kernel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-64k-debug-modules-extra
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-debug-core as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug-core
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-doc as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-doc
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-64k-debug as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-debug
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-64k-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-modules-extra
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-devel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-devel
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-uki-virt-addons as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-uki-virt-addons
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel.src as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel?arch=src
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-debug as a component of Red Hat Enterprise Linux 6 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- no fix planned: Out of support scope
perf as a component of Red Hat Enterprise Linux 6 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/perf
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- no fix planned: Out of support scope
kernel-doc as a component of Red Hat Enterprise Linux 7 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-doc
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-doc as a component of Red Hat Enterprise Linux 7 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-doc
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel.src as a component of Red Hat Enterprise Linux 7 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel?arch=src
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-debug as a component of Red Hat Enterprise Linux 8 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-ipaclones-internal as a component of Red Hat Enterprise Linux 8 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-ipaclones-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-debug-kvm as a component of Red Hat Enterprise Linux 8 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-debug-kvm
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-selftests-internal as a component of Red Hat Enterprise Linux 8 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-selftests-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-zfcpdump-modules as a component of Red Hat Enterprise Linux 8 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-zfcpdump-modules
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-64k-core as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-64k-core
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-64k-debug-modules-partner as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-64k-debug-modules-partner
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-core as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-core
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-debug-modules-internal as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug-modules-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-kmap-internal as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-kmap-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-64k-core as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-core
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-64k-debug-modules-internal as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-debug-modules-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-64k-modules-partner as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-modules-partner
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-debug-modules-extra as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-debug-modules-extra
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-rt-modules-internal as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-modules-internal
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-uki-virt-addons as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-uki-virt-addons
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
kernel-zfcpdump-modules-partner as a component of Red Hat Enterprise Linux 9 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-zfcpdump-modules-partner
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known affected
Vendor assessment for this product only.
pkg:oci/ose-rhel-coreos-9?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-9
- workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
- none available: Fix deferred
References
Advisories
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98377.json Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-95532 EUVD · EUVD-2026-95532
Technical & other
- https://git.kernel.org/stable/c/3d531429524df2c7116579306640283fea68bcf0CVE record · Linux · Updated 2026-10-21T12:55:00.318Z
NVD · CVE-2026-98377 · Updated 2026-10-21T13:21:28.007 - https://git.kernel.org/stable/c/40a5cc4b7251c74f3341332a226d02200e96bccfCVE record · Linux · Updated 2026-10-21T12:55:00.318Z
NVD · CVE-2026-98377 · Updated 2026-10-21T13:21:28.007 - https://git.kernel.org/stable/c/f42562dd027dc4ed103fae17b2206e73ea1963c4CVE record · Linux · Updated 2026-10-21T12:55:00.318Z
NVD · CVE-2026-98377 · Updated 2026-10-21T13:21:28.007 - https://git.kernel.org/stable/c/59af43ccece4d2d8b62e9e3ccc96b6e2e793bcdcCVE record · Linux · Updated 2026-10-21T12:55:00.318Z
NVD · CVE-2026-98377 · Updated 2026-10-21T13:21:28.007 - https://git.kernel.org/stable/c/ab888242fce4f16f6c4d4c6ec53939ad36aa3b3aCVE record · Linux · Updated 2026-10-21T12:55:00.318Z
NVD · CVE-2026-98377 · Updated 2026-10-21T13:21:28.007 - https://access.redhat.com/security/cve/CVE-2026-98377 Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://bugzilla.redhat.com/show_bug.cgi?id=2548389 Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://www.cve.org/CVERecord?id=CVE-2026-98377 Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://nvd.nist.gov/vuln/detail/CVE-2026-98377 Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98377.mbox Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00
- https://kernelcve.org/list/?q=CVE-2026-98377 Red Hat · CVE-2026-98377 · Updated 2026-10-21T17:53:53+00:00