tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
Summary
| CVE | CVE-2026-63994 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-19 16:17:38 UTC |
| Updated | 2026-07-20 15:17:01 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001760000 probability, percentile 0.073910000 (date 2026-07-20)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 95b6d772bfe788331d9742d73eaa12e113b2adc4 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 7254aef4d1a7e18e887af9010e2f2dc34806789b git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f bf8b3f34c37c162357138e7c0942723b8b94fed1 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 76cd9398a0470257ab765bdf5f358a2af2e17934 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 50750d86a2e5266aba0c295483b3397843198b11 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 6dff77899b9e9fe5d854abda3a98ad04e7229ef7 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f f3f204541f280a6ecb04503a0d6794d93990ca43 git | Not specified |
| CNA | Linux | Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f b4bc94353050b1fa7b702bd4c6600710dd926cff git | Not specified |
| CNA | Linux | Linux | affected 5.9 | Not specified |
| CNA | Linux | Linux | unaffected 5.9 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.259 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.210 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.176 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.143 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.93 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.35 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.12 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789b | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cff | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.