Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — bpf: Scrub packet on bpf_redirect_peer
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U N N H 5.5 .0032 25.3 —
AFFECTED
Product Versions Fixed
Linux 9aa1206e8f48222f35a0c809f33b2f4aaa1e2661 – —
Linux 5.10 – 6.1.139
TIMELINE
Apr 16 Reserved by Linux
May 20 Published (CNA: Linux)
Jul 30 RESCORED — CVE-2025-37959 (Linux). CVSS 9.4 → 5.5 (NVD).
Description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Scrub packet on bpf_redirect_peer
When bpf_redirect_peer is used to redirect packets to a device in
another network namespace, the skb isn't scrubbed. That can lead skb
information from one namespace to be "misused" in another namespace.
As one example, this is causing Cilium to drop traffic when using
bpf_redirect_peer to redirect packets that just went through IPsec
decryption to a container namespace. The following pwru trace shows (1)
the packet path from the host's XFRM layer to the container's XFRM
layer where it's dropped and (2) the number of active skb extensions at
each function.
NETNS MARK IFACE TUPLE FUNC
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm_rcv_cb
.active_extensions = (__u8)2,
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm4_rcv_cb
.active_extensions = (__u8)2,
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 gro_cells_receive
.active_extensions = (__u8)2,
[...]
4026533547 0 eth0 10.244.3.124:35473->10.244.2.158:53 skb_do_redirect
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv_core
.active_extensions = (__u8)2,
[...]
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 udp_queue_rcv_one_skb
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_policy_check
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_decode_session
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 security_xfrm_decode_session
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 kfree_skb_reason(SKB_DROP_REASON_XFRM_POLICY)
.active_extensions = (__u8)2,
In this case, there are no XFRM policies in the container's network
namespace so the drop is unexpected. When we decrypt the IPsec packet,
the XFRM state used for decryption is set in the skb extensions. This
information is preserved across the netns switch. When we reach the
XFRM policy check in the container's netns, __xfrm_policy_check drops
the packet with LINUX_MIB_XFRMINNOPOLS because a (container-side) XFRM
policy can't be found that matches the (host-side) XFRM state used for
decryption.
This patch fixes this by scrubbing the packet when using
bpf_redirect_peer, as is done on typical netns switches via veth
devices except skb->mark and skb->tstamp are not zeroed.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| April 16, 2025 | Reserved | Reserved by Linux |
| May 20, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-37959 (Linux). CVSS 9.4 → 5.5 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 9aa1206e8f48222f35a0c809f33b2f4aaa1e2661 | — |
| Linux | Linux | — | 5.10 | 6.1.139 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-37959 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.