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CVE

CVE-2026-63994

tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
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CVE

CVE-2026-63994

tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()

In the Linux kernel, the following vulnerability has been resolved:

tunnels: load network headers after skbcow() in iptunnelpmtudbuildicmp[v6]()

Sashiko found that iptunnelpmtudbuild_icmp() and

iptunnelpmtudbuildicmpv6() were caching iphdr() 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 skbresetnetwork_header() calls which were not needed.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.8
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
C
H
U
-

Related Resources

No items found.

References

https://git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11, https://git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7, https://git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789b, https://git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934, https://git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4, https://git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cff, https://git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1, https://git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63994.json, https://nvd.nist.gov/vuln/detail/CVE-2026-63994, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Severity

9.8

CVSS Score
0
10

Basic Information

Base CVSS
9.8
EPSS Probability
0.00514%
EPSS Percentile
0.41792%
Introduced Version
4cb47a8644cc9eb8ec81190a50e79e6530d0297f,5.9.0,5.11.0,5.16.0,6.2.0,6.7.0,6.13.0,6.19.0,0
Fix Available
b4bc94353050b1fa7b702bd4c6600710dd926cff,5.10.259,5.15.210,6.1.176,6.6.143,6.12.93,6.18.35,7.0.12,6.1.176-1,6.12.94-1,7.0.0-28.28~24.04.1,7.0.0-1016.16~24.04.1,7.0.0-28.28.1~24.04.3,0:5.15.0-323.211.3.3.el8uek,0:6.12.0-206.104.3.3.el9uek,0:5.15.0-323.211.3.3.el9uek,0:6.12.0-206.104.3.3.el10uek,0:5.10.259-258.1043.amzn2,0:1.0-0.amzn2,0:5.15.210-148.245.amzn2,1:6.18.35-68.127.amzn2023,1:1.0-0.amzn2023,1:6.1.176-220.358.amzn2023,1:6.12.94-123.174.amzn2023

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