tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63992
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:38 UTC
Updated2026-07-20 15:17:00 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: tunnels: do not assume transport header in iptunnel_pmtud_check_icmp() In some cases, iptunnel_pmtud_check_icmp() can be called while skb transport header is not set. This triggers an out-of-bound access, because (typeof(skb->transport_header))~0U is 65535. Access the icmp header based on IPv4 network header, after making sure icmp->type is present in skb linear part. Note that iptunnel_pmtud_check_icmpv6()) is fine.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

EPSS: 0.001760000 probability, percentile 0.073840000 (date 2026-07-20)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 5a92cb45e34749865d03daf8d3500f77b5f6644c git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f c7b7ec3e69e673c0d6b57f74d21da50c485c598e git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 7f4f7efe7f30edd29c4988de01728bf2398217e4 git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f a096b6e34f602950af9a2b0856cd93a5f4c276d7 git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 43368636c663cff6e59dde93cf4b8e43ac28eb93 git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f cb549df9ce4ee15c9d5b19ddab12cf2128e4313c git Not specified
CNA Linux Linux affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f 509323077ef79a26ba0c60bb556e45c12c398b2d 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

ReferenceSourceLinkTags
git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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