tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()
Published Jul 19, 2026
9.1
CRITICALCVSS 3.1
EPSS 0.51%
Description
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.
Affected products
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- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
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- Version
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- Version 5.9StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<5.9
- Version 5.10.259StatusunaffectedConstraints<=5.10.*
- Version 5.15.210StatusunaffectedConstraints<=5.15.*
- Version 6.1.176StatusunaffectedConstraints<=6.1.*
- Version 6.12.93StatusunaffectedConstraints<=6.12.*
- Version 6.18.35StatusunaffectedConstraints<=6.18.*
- Version 6.6.143StatusunaffectedConstraints<=6.6.*
- Version 7.0.12StatusunaffectedConstraints<=7.0.*
- Version 7.1StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
Red Hat Enterprise Linux 10
kernel
Affected
Red Hat Enterprise Linux 6
kernel
Out of support scope
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Affected
Red Hat Enterprise Linux 8
kernel-rt
Affected
Red Hat Enterprise Linux 9
kernel
Affected
Red Hat Enterprise Linux 9
kernel-rt
Affected
Red Hat Hardened Images
erlang27
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | n/a |
| Red Hat Enterprise Linux 9 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | n/a |
| Red Hat Hardened Images | erlang27 | Not affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (13)
- https://access.redhat.com/security/cve/CVE-2026-63992 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2502431 Issue Tracking
- https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93
- https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d
- https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c
- https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4
- https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7
- https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e
- https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c
- https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec
- https://lore.kernel.org/linux-cve-announce/2026071904-CVE-2026-63992-2846@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2026-63992
- https://www.cve.org/CVERecord?id=CVE-2026-63992
Change history (0)
No recorded changes yet.