CVE-2026-63994
tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
CRITICAL 9.8
At a glance
- Source
- NVD
- EPSS
- EPSS 0.51 % · percentile 44 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-416 — Use After Free
References
- https://git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4
- https://git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789b
- https://git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1
- https://git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934
- https://git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11
- https://git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7
- https://git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43
- https://git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cff
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | Linux |
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-45567
- GCVE · GCVE-0-2026-63994
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1335 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1288 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1287 — Multiples vulnérabilités dans le noyau Linux de Red Hat · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1286 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1252 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1229 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1203 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1162 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1091 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1064 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1029 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.9 < 5.10.259cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.210cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.176cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.143cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.93cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.35cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 7.0.12cpe: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:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 95b6d772bfe788331d9742d73eaa12e113b2adc4 ; affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 7254aef4d1a7e18e887af9010e2f2dc34806789b ; affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < bf8b3f34c37c162357138e7c0942723b8b94fed1 ; affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 76cd9398a0470257ab765bdf5f358a2af2e17934 ; affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 50750d86a2e5266aba0c295483b3397843198b11 ; affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f < 6dff77899b9e9fe5d854abda3a98ad04e7229ef7 |
| Linux · Linux | affected 5.9 ; unaffected 0 < 5.9 ; unaffected 5.10.259 ≤ 5.10.* ; unaffected 5.15.210 ≤ 5.15.* ; unaffected 6.1.176 ≤ 6.1.* ; unaffected 6.6.143 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |