CVE-2023-53600

tunnels: fix kasan splat when generating ipv4 pmtu error

State: Published
Severity: 9.1 Critical
Published: Oct 4, 2025
Updated: Oct 15, 2026
Reserved: Oct 4, 2025

Description

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

tunnels: fix kasan splat when generating ipv4 pmtu error

If we try to emit an icmp error in response to a nonliner skb, we get

BUG: KASAN: slab-out-of-bounds in ip_compute_csum+0x134/0x220 Read of size 4 at addr ffff88811c50db00 by task iperf3/1691 CPU: 2 PID: 1691 Comm: iperf3 Not tainted 6.5.0-rc3+ #309 [..] kasan_report+0x105/0x140 ip_compute_csum+0x134/0x220 iptunnel_pmtud_build_icmp+0x554/0x1020 skb_tunnel_check_pmtu+0x513/0xb80 vxlan_xmit_one+0x139e/0x2ef0 vxlan_xmit+0x1867/0x2760 dev_hard_start_xmit+0x1ee/0x4f0 br_dev_queue_push_xmit+0x4d1/0x660 [..]

ip_compute_csum() cannot deal with nonlinear skbs, so avoid it. After this change, splat is gone and iperf3 is no longer stuck.

Scores

CVSS	Score	Vector	Source
3.1	9.1 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before 5850c391fd7e25662334cb3cbf29a62bcbff1084Affected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before e95808121953410db8c59f0abfde70ac0d34222cAffected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before da5f42a6e7485fbb7a6dbd6a2b3045e19e4df5ccAffected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before fe6a9f7516735be9fdabab00e47ef7a3403a174dAffected 4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before 6a7ac3d20593865209dceb554d8b3f094c6bd940Affected
LinuxLinux	5.9Affected before 5.9Not affected 5.10.191 through 5.10.Not affected 5.15.127 through 5.15.Not affected 6.1.46 through 6.1.Not affected 6.4.11 through 6.4.Not affected 6.5 and laterNot affected

Product

Versions

LinuxLinux

4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before 5850c391fd7e25662334cb3cbf29a62bcbff1084Affected
4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before e95808121953410db8c59f0abfde70ac0d34222cAffected
4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before da5f42a6e7485fbb7a6dbd6a2b3045e19e4df5ccAffected
4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before fe6a9f7516735be9fdabab00e47ef7a3403a174dAffected
4cb47a8644cc9eb8ec81190a50e79e6530d0297f to before 6a7ac3d20593865209dceb554d8b3f094c6bd940Affected

LinuxLinux

5.9Affected
before 5.9Not affected
5.10.191 through 5.10.*Not affected
5.15.127 through 5.15.*Not affected
6.1.46 through 6.1.*Not affected
6.4.11 through 6.4.*Not affected
6.5 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.