vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
Published Jul 19, 2026
9.8
CRITICALCVSS 3.1
EPSS 0.51%
Description
skb_tunnel_check_pmtu() can change skb->head.
Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.
Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c.
Found by Sashiko.
Affected products
-
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version
-
- 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 |
| |||||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
- ≥ 5.9 · < 5.10.259
- ≥ 5.11 · < 5.15.210
- ≥ 5.16 · < 6.1.176
- ≥ 6.2 · < 6.6.143
- ≥ 6.7 · < 6.12.93
- ≥ 6.13 · < 6.18.35
- ≥ 6.19 · < 7.0.12
- 7.1
- 7.1
- 7.1
- 7.1
- 7.1
No data.
Red Hat Enterprise Linux 10
kernel-0:6.12.0-211.52.1.el10_2
Fixed · RHSA-2026:64775
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not 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-0:6.12.0-211.52.1.el10_2 | Fixed | RHSA-2026:64775 |
| Red Hat Enterprise Linux 6 | kernel | Not affected | 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 | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not 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 (14)
- https://access.redhat.com/security/cve/CVE-2026-63993 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2502369 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-45566 Advisory
- https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7
- https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb
- https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0
- https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
- https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd
- https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a
- https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea
- https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d
- https://lore.kernel.org/linux-cve-announce/2026071905-CVE-2026-63993-165e@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2026-63993
- https://www.cve.org/CVERecord?id=CVE-2026-63993
Change history (0)
No recorded changes yet.