CVE-2026-63994
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()…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.51%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.51% probability · 44th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://git.kernel.org/stable/c/50750d86a2e5266aba0c295483b3397843198b11Patch
- https://git.kernel.org/stable/c/6dff77899b9e9fe5d854abda3a98ad04e7229ef7Patch
- https://git.kernel.org/stable/c/7254aef4d1a7e18e887af9010e2f2dc34806789bPatch
- https://git.kernel.org/stable/c/76cd9398a0470257ab765bdf5f358a2af2e17934Patch
- https://git.kernel.org/stable/c/95b6d772bfe788331d9742d73eaa12e113b2adc4Patch
- https://git.kernel.org/stable/c/b4bc94353050b1fa7b702bd4c6600710dd926cffPatch
- https://git.kernel.org/stable/c/bf8b3f34c37c162357138e7c0942723b8b94fed1Patch
- https://git.kernel.org/stable/c/f3f204541f280a6ecb04503a0d6794d93990ca43Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.