Critical severity9.8NVD Advisory· Published Jul 19, 2026· Updated Oct 16, 2026
CVE-2026-63994
CVE-2026-63994
Description
In the Linux kernel, the following vulnerability has been resolved:
tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
Sashiko found that iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr() before an skb_cow() call which can reallocate skb->head.
Fix this possible UAF by initializing the local variables after the skb_cow() call.
Remove skb_reset_network_header() calls which were not needed.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
97(expand)+ 6 more
- (no CPE)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*range: >=5.9,<5.10.259
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
- osv-coords90 versionspkg:rpm/opensuse/dtb-aarch64&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-64kb&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-default-base&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-kvmsmall&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-obs-qa&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-rt&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-zfcpdump&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-64k-corepkg:rpm/almalinux/kernel-debugpkg:rpm/almalinux/kernel-tools-libspkg:rpm/almalinux/kernel-cross-headerspkg:rpm/almalinux/kernel-rt-64k-debug-modules-corepkg:rpm/almalinux/kernel-abi-stablelistspkg:rpm/opensuse/kernel-syms&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-azure&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-64k-modules-extrapkg:rpm/opensuse/kernel-source&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-rt-debug-corepkg:rpm/almalinux/kernel-rt-debug-modulespkg:rpm/almalinux/kernel-rt-debug-modules-extrapkg:rpm/almalinux/kernel-rt-develpkg:rpm/almalinux/kernel-rt-modulespkg:rpm/almalinux/bpftoolpkg:rpm/almalinux/kernel-develpkg:rpm/almalinux/kernel-tools-libs-develpkg:rpm/almalinux/kernel-zfcpdump-modulespkg:rpm/almalinux/kernel-zfcpdump-modules-extrapkg:linux/kernelpkg:rpm/opensuse/kernel-docs&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-debug-develpkg:rpm/almalinux/kernel-docpkg:rpm/almalinux/kernel-modules-extrapkg:rpm/almalinux/kernel-zfcpdumppkg:rpm/almalinux/kernel-rt-debugpkg:rpm/almalinux/kernel-rt-modules-extrapkg:rpm/almalinux/kernel-headerspkg:rpm/almalinux/kernel-modulespkg:rpm/almalinux/kernel-toolspkg:rpm/opensuse/kernel-obs-build&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-debug-modulespkg:rpm/opensuse/kernel-default&distro=openSUSE%20Leap%2016.0pkg:rpm/almalinux/kernel-corepkg:rpm/almalinux/perfpkg:rpm/almalinux/kernel-rt-debug-develpkg:rpm/almalinux/kernelpkg:rpm/almalinux/kernel-64k-debugpkg:rpm/almalinux/kernel-64k-debug-corepkg:rpm/almalinux/kernel-64k-debug-develpkg:rpm/almalinux/kernel-64k-debug-devel-matchedpkg:rpm/almalinux/kernel-64k-debug-modulespkg:rpm/almalinux/kernel-debug-devel-matchedpkg:rpm/almalinux/kernel-rtpkg:rpm/almalinux/kernel-rt-corepkg:rpm/almalinux/kernel-debug-corepkg:rpm/almalinux/kernel-debug-modules-extrapkg:rpm/almalinux/kernel-zfcpdump-corepkg:rpm/almalinux/kernel-zfcpdump-develpkg:rpm/almalinux/python3-perfpkg:rpm/almalinux/kernel-64kpkg:rpm/almalinux/kernel-64k-debug-modules-corepkg:rpm/almalinux/kernel-64k-debug-modules-extrapkg:rpm/almalinux/kernel-64k-develpkg:rpm/almalinux/kernel-64k-devel-matchedpkg:rpm/almalinux/kernel-64k-modulespkg:rpm/almalinux/kernel-64k-modules-corepkg:rpm/almalinux/kernel-debug-modules-corepkg:rpm/almalinux/kernel-debug-uki-virtpkg:rpm/almalinux/kernel-devel-matchedpkg:rpm/almalinux/kernel-modules-corepkg:rpm/almalinux/kernel-modules-extra-matchedpkg:rpm/almalinux/kernel-rt-64kpkg:rpm/almalinux/kernel-rt-64k-corepkg:rpm/almalinux/kernel-rt-64k-debugpkg:rpm/almalinux/kernel-rt-64k-debug-corepkg:rpm/almalinux/kernel-rt-64k-debug-develpkg:rpm/almalinux/kernel-rt-64k-debug-modulespkg:rpm/almalinux/kernel-rt-64k-develpkg:rpm/almalinux/kernel-rt-64k-modules-corepkg:rpm/almalinux/kernel-rt-64k-modules-extrapkg:rpm/almalinux/kernel-rt-debug-modules-corepkg:rpm/almalinux/kernel-rt-modules-corepkg:rpm/almalinux/kernel-uki-virtpkg:rpm/almalinux/kernel-uki-virt-addonspkg:rpm/almalinux/kernel-zfcpdump-devel-matchedpkg:rpm/almalinux/kernel-zfcpdump-modules-corepkg:rpm/almalinux/libperfpkg:rpm/almalinux/rtlapkg:rpm/almalinux/rvpkg:rpm/almalinux/kernel-rt-64k-debug-modules-extrapkg:rpm/almalinux/kernel-rt-64k-modules
< 6.12.0-160000.37.1+ 89 more
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1.160000.2.19
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: >= 5.9.0, < 5.10.259
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.rt7.512.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 4.18.0-553.171.1.el8_10
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
- (no CPE)range: < 6.12.0-211.63.1.el10_2
Patches
Vulnerability mechanics
References
8- git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11nvdPatch
- git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7nvdPatch
- git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789bnvdPatch
- git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934nvdPatch
- git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4nvdPatch
- git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cffnvdPatch
- git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1nvdPatch
- git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43nvdPatch
News mentions
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